LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA 

GIFT    OF 


Class 


BY  THE  AUTHOR    OF  THIS    VOLUME. 


METEORIC    ASTRONOMY: 

A   TREATISE   ON 

SHOOTING   STARS,  FIRE   BALLS, 
AND   AEROLITES. 

BY   DANIEL  KIRKWOOD,  LL.D. 

12mo.     Extra  Cloth.     $1.5O. 

*#*  For  sale  by  Booksellers  generally,  or  will  be  sent  by  mail, 
postpaid,  on  receipt  of  the  price  by 

J,  B,  LIPPINCOTT  &  00,,  Publishers, 

715  and  717  Market  St.,  Philadelphia. 


Fig.  1. 


THE  SOLAR  SYSTEM. 


[Frontispiece.] 


COMETS  AND  METEORS 


THEIR  PHENOMENA  IN  ALL  AGES; 


THEIR    MUTUAL    RELATIONS; 


THEORY  OF  THEIR  ORIGIN. 


BY 


DANIEL    KIRK  WOOD,   LL.D., 

PROFESSOR   OF   MATHEMATICS   IN   INDIANA   UNIVERSITY,  AND   AUTHOR   OF    "  METEORIC 
ASTRONOMY." 


PHILADELPHIA: 

J.    B.    LIPPINCOTT    &    CO. 

1873. 


Entered  according  to  Act  of  Congress,  in  the  year  1873,  by 

DANIEL    KIRKWOOD,  LL.D., 
In  the  Office  of  the  Librarian  of  Congress  at  Washington. 


te. 


PREFACE. 


THE  origin  of  meteoric  astronomy,  as  a  science, 
dates  from  the  memorable  star-shower  of  1833. 
Soon  after  that  brilliant  display  it  was  found  that 
similar  phenomena  had  been  witnessed,  at  nearly 
regular  intervals,  in  former  times.  This  discovery 
led  at  once  to  another  no  less  important,  viz. :  that 
the  nebulous  masses  from  which  such  showers  are 
derived  revolve  about  the  sun  in  paths  intersecting 
the  earth's  orbit.  The  theory  that  these  meteor- 
clouds  are  but  the  scattered  fragments  of  disin- 
tegrated comets  was  announced  by  several  astron- 
omers in  1867: — a  theory  confirmed  in  a  remark- 
able manner  by  the  shower  of  meteors  from  the 
debris  of  Biela's  comet  on  the^  27th  of  November, 
1872. 

To  gratify  the  interest  awakened  in  the  public 
mind  by  the  discoveries  here  named,  is  the  main 
design  of  the  following  work.  Among  the  subjects 
considered  are,  cometary  astronomy ;  aerolites,  with 
the  phenomena  attending  their  fall;  the  most  bril- 

3 

219378 


4  PREFACE. 

liant  star-showers  of  all  ages;  and  the  origin  of 
comets,  aerolites,  and  falling  stars. 

It  may  be  proper  to  remark  that  the  language 
used  by  the  writer  in  a  volume*  published  several 
years  since,  and  now  nearly  out  of  print,  has  been 
occasionally  adopted  in  the  following  treatise. 

BLOOMINGTON,  INDIANA,  April,  1873. 

*  Meteoric  Astronomy. 


CONTENTS. 


PREFACE 


CHAPTER    I. 
A  GENERAL  VIEW  or  THE  SOLAR  SYSTEM  ....       9 

CHAPTER   II. 

COMETS 13 

COMETS  VISIBLE  IN  THE  DAY-TIME   .        .        .        .        .15 
PERIODIC  COMETS^ 18 

CHAPTER   III. 

COMETS    WHOSE    ELEMENTS    INDICATE    PERIODICITY,    BUT 
WHOSE  RETURNS  HAVE  NOT  BKKN  RECOGNIZED         .        .     31 

CHAPTER  IV. 
OTHER  REMARKABLE  COMETS 39 

CHAPTER  V. 
THE  POSITION   AND  ARRANGEMENT  OF   COMETARY  ORBITS    43 

CHAPTER   VI. 
THE  DISINTEGRATION  OF  COMETS 49 

CHAPTER  VII. 

METEORIC  STONES 57 

1*  5 


CONTENTS. 


CHAPTER   VIII. 

PAOE. 

SHOOTING-STARS — METEORS  OF  NOVEMBER  14      .  69 


CHAPTER  IX. 
OTHER  METEORIC  STREAMS 82 

CHAPTER  X. 
THE  ORIGIN  OF  COMETS  AND  METEORS  94 


I. 


COMETS. 


COMETS  AND  METEORS. 


CHAPTER  I. 

A    GENERAL    VIEW    OF   THE    SOLAR    SYSTEM. 

4) 

A  DESCRIPTIVE  treatise  on  COMETS  and  METEORS 
may  properly  be  preceded  by  a  brief  general  view 
of  the  planetary  system  to  which  these  bodies  are 
related,  and  by  which  their  motions,  in  direction 
and  extent,  are  largely  influenced. 

THE  SOLAR  SYSTEM  consists  of  the  sun,  together 
with  the  planets,  comets,  and  meteors  which  revolve 
around  it  as  the  centre  of  their  motions.  The  sun 
is  the  great  controlling  orb  of  this  system,  and  the 
source  of  light  and  heat  to  its  various  members. 
Its  magnitude  is  one  million  three  hundred  thou- 
sand times  greater  than  that  of  the  earth,  and"  it 
contains  more  than  seven  hundred  times  as  much 
matter  as  all  the  planets  put  together. 

Mercury  is  the  nearest  planet  to  the  sun;  its 
mean  distance  being  about  35,400,000  miles.  Its 
diameter  is  3000  miles,  and  it  completes  its  orbital 
revolution  in  88  days. 

Venus,  the  next  member  of  the  system,  is  some- 
times our  morning  and  sometimes  our  evening  star. 
Its  magnitude  is  almost  exactly  the  same  as  that  of 
the  earth.  It  revolves  round  the  sun  in  225  days. 

9 


10  COMETS    AND    METEORS. 

The  earth  is  the  third  planet  from  the  sun  in 
the  order  of  distance ;  the  radius  of  its  orbit  being 
about  92,000,000  miles.  It  is  attended  by  one  sat- 
ellite,— the  moon, — the  diameter  of  which  is  2160 
miles. 

Mars  is  the  first  planet  exterior  to  the  earth's 
orbit.  It  is  considerably  smaller  than  the  earth, 
and  has  no  satellite.  It  revolves  round  the  sun  in 
687  days. 

The  Asteroids. — Since  the  commencement  of  the 
present  Century  a  remarkable  zone  of  telescopic 
planets  has  been  discovered  immediately  exterior  to 
the  orbit  of  Mars.  These  bodies  are  extremely 
small;  some  of  them  probably  containing  less  mat- 
ter than  the  largest  mountains  on  the  earth's  sur- 
face. 131  members  of  the  group  are  known  at 
present,  and  the  number  is  annually  increasing. 

Jupiter,  the  first  planet  exterior  to  the  asteroids, 
is  nearly  500,000,000  miles  from  the  sun,  and  re- 
volves round  it  in  a  little  less  than  12  years.  This 
planet  is  86,000  miles  in  diameter,  and  contains 
more  than  twice  as  much  matter  as  all  the  other 
planets,  primary  and  secondary,  put  together.  Ju- 
piter is  attended  by  four  moons  or  satellites. 

Saturn  is  the  sixth  of  the  principal  planets  in  the 
order  of  distance.  Its  orbit  is  about  400,000,000 
miles  beyond  that  of  Jupiter.  This  planet  is  at- 
tended by  eight  satellites,  and  is  surrounded  by 
three  broad  flat  rings.  Saturn  is  73,000  miles  in 
diameter,  and  its  mass  or  quantity  of  matter  is  more 
than  that  of  all  the  other  planets  except  Jupiter. 

Uranus  is  at  double  the  distance  of  Saturn,  or 
nineteen  times  that  of  the  earth.  Its  diameter  is 


A   GENERAL   VIEW   OF   THE   SOLAR   SYSTEM.          11 

about  34,000  miles,  and  its  period  of  revolution  84 
years.  It  is  attended  by  at  least  four  satellites. 

Neptune  is  the  most  remote  known  member  of 
the  system;  its  distance  being  2,800,000,000  miles. 
It  is  somewhat  larger  than  Uranus;  has  certainly 
one  satellite,  and  probably  several  more.  Its  period 
is  about  165  years.  A  cannon-ball  flying  outward 
from  the  sun  at  the  uniform  velocity  of  500  miles 
per  hour  would  not  reach  the  orbit  of  Neptune  in 
less  than  639  years. 

These  planets  all  move  round  the  sun  in  the  same 
direction, — from  west  to  east.  Their  motions  are 
nearly  circular,  and  also  nearly  in  the  same  plane. 
Their  orbits,  except  that  of  Neptune,  are  repre- 
sented in  the  frontispiece.  It  is  proper  to  remark, 
however,  that  all  representations  of  the  solar  system 
by  maps  and  planetariums  must  give  an  exceedingly 
erroneous  view  either  of  the  magnitudes  or  dis- 
tances of  its  various  members.  If  the  earth,  for 
instance,  be  denoted  by  a  ball  half  an  inch  in  di- 
ameter, the  diameter  of  the  sun,  according  to  the 
same  scale  (16,000  miles  to  the  inch),  will  be  between 
four  and  five  feet;  that  of  the  earth's  orbit,  about 
1000  feet;  while  that  of  Neptune's  orbit  will  be 
nearly  six  miles.  To  give  an  accurate  representa- 
tion of  the  solar  system  at  a  single  view  is  therefore 
plainly  impracticable. 

THE  ZODIACAL  LIGHT. — This  term  was  first  applied 
by  Dominic  Cassini,  in  1683,  to  a  faint  nebulous 
aurora,  somewhat  resembling  the  milky  way,  ap- 
parently of  a  conical  or  lenticular  form,  having  its 
base  toward  the  sun  and  its  axis  nearly  in  the  di- 
rection of  the  ecliptic.  The  most  favorable  time  for 


12  COMETS   AND   METEORS. 

observing  it  is  when  its  axis  is  most  nearly  perpen- 
dicular to  the  horizon.  This,  in  our  latitudes,  oc- 
curs in  March,  for  the  evening,  and  in  October,  for 
the  morning.  The  angular  distance  of  its  vertex 
from  the  sun  is  frequently  seventy  or  eighty  de- 
grees, while  sometimes,  though  rarely  (except  within 
the  tropics),  it  exceeds  even  one  hundred  degrees. 
It  was  noticed  in  the  latter  part  of  the  16th  century 
by  Tycho  Brahe.  The  first  accurate  description  of 
the  phenomenon  was  given,  however,  by  Cassini. 
This  astronomer  supposed  the  appearance  to  be  pro- 
duced by  the  blended  light  of  innumerable  bodies 
too  small  to  be  separately  observed, — a  theory  still 
very  generally  accepted.  In  other  words,  the  zo- 
diacal light  is  probably  a  swarm  of  infinitesimal 
planets;^  the  greater  part  of  the  cluster  being  inte- 
rior to  Mercury's  orbit. 

The  distances  between  the  different  members  of 
our  planetary  system,  vast  as  they  may  seem,  sink 
into  insignificance  when  compared  with  the  inter- 
vals which  separate  us  from  the  so-called  fixed  stars. 
Alpha  Centauri,  the  nearest  of  those  twinkling  lu- 
minaries, is  7000  times  more  distant  than  Neptune 
from  the  sun.  Even  light  itself,  which  moves 
185,000  miles  in  a  second,  is  more  than  three  years 
in  traversing  the  mighty  interval. 


CHAPTER    II. 

COMETS. 

THE  term  comet — which  signifies  literally  a  hairy 
star — may  be  applied  to  all  bodies  that  revolve  about 
the  sun  in  very  eccentric  orbits.  The  sudden  ap- 
pearance, vast  dimensions,  and  extraordinary  aspect 
of  these  celestial  wanderers,  together  with  their  rapid 
and  continually  varying  motions,  have  never  failed 
to  excite  the  attention  and  wonder  of  all  observers. 
Nor  is  it  surprising  that  in  former  times,  when  the 
nature  of  their  orbits  was  wholly  unknown,  they 
should  have  been  looked  upon  as  omens  of  impend- 
ing evil,  or  messengers  of  an  angry  Deity.  Even 
now,  although  modern  science  has  reduced  their 
motions  to  the  domain  of  law,  determined  approxi- 
mately their  orbits,  and  assigned  in  a  number  of 
instances  their  periods,  the  interest  awakened  by 
their  appearance  is  in  some  respects  still  unabated. 

The  special  points  of  dissimilarity  between  planets 
and  comets  are  the  following: — The  former  are 
dense,  and,  so  far  as  we  know,  solid  bodies;  the 
latter  are  many  thousand  times  rarer  than  the  earth's 
atmosphere.  The  planets  all  move 'from  west  to 
east;  many  comets  revolve  in  the  opposite  direction. 
The  planetary  orbits  are  but  slightly  inclined  to  the 
plane  of  the  ecliptic;  those  of  comets  may  have  any 
inclination  whatever.  *The  planets  are  observed  in 

2  13 


14  COMETS    AND    METEORS. 

all  parts  of  their  orbits;  comets,  only  in  those  parts 
nearest  the  sun. 

The  larger  comets  are  attended  by  a  tail,  or  train 
of  varying  dimensions,  extending  generally  in  a 
direction  opposite  to  that  of  the  sun.  The  more 
condensed  part,  from  which  the  tail  proceeds,  is 
called  the  nucleus;  and  the  nebulous  envelope  imme- 
diately surrounding  the  nucleus  is  sometimes  termed 
the  coma.  These  different  parts  are  seen  in  Fig.  2, 
which  represents  the  great  comet  of  1811. 

Zeno,  Democritus,  and  other  Greek  philosophers 
held  that  comets  were  produced  by  the  collection  of 
several  stars  into  clusters.  Aristotle  taught  that 
they  were  formed  by  exhalations,  which,  rising  from 
the  earth's  surface,  ignited  in  the  upper  regions  of 
the  atmosphere.  This  hypothesis,  through  the  great 
influence  of  its  author,  was  generally  received  for 
almost  two  thousand  years.  Juster  views,  however, 
were  entertained  by  the  celebrated  Seneca,  who 
maintained  that  comets  ought  to  be  ranked  among 
the  permanent  works  of  nature,  and  that  their  dis- 
appearance was  not  an  extinction,  but  simply  a 
passing  beyond  the  reach  of  our  vision.  The  ob- 
servations of  Tycho  Brahe  first  established  the  fact 
that  comets  move  through  the  planetary  spaces  far 
beyond  the  limits  of  our  atmosphere.  The  illustrious 
Dane,  however,  supposed  them  to  move  in  circular 
orbits.  Kepler,  on  the  other  hand,  was  no  less  in 
error  in  considering  their  paths  to  be  rectilinear. 
James  Bernoulli  supposed  comets  to  be  the  satel- 
lites of  a  very  remote  planet,  invisible  on  account 
of  its  great  distance, — such  satellites  being  seen  only 
in  the  parts  of  their  orbits  ifearest  the  earth.  Still 


THE  GREAT  COMET  OY  1811. 


rage  II. 


COMETS.  15 

more  extravagant  was  the  hypothesis  of  Descartes, 
who  held  that  they  were  originally  fixed  stars,  which, 
having  gradually  lost  their  light,  could  no  longer 
retain  their  positions,  but  were  involved  in  the  vor- 
tices of  the  neighboring  stars,  when  such  as  were 
thus  brought  within  the  sphere  of  the  sun's  illumi- 
nating power  again  became  visible. 

Comets  visible  in  the  daytime. 

Comets  of  extraordinary  brilliancy  have  some- 
times been  seen  during  the  daytime.  At  least 
thirteen  authentic  instances  of  this  phenomenon 
have  been  recorded  in  history.  The  first  was  the 
comet  which  appeared  about  the  year  43  B.C.,  just 
after  the  assassination  of  Julius  Csesar.  The  Romans 
called  it  the  Julium  Sidus,  and  regarded  it  as  a  celes- 
tial chariot  sent  to  convey  the  soul  of  Caesar  to  the 
skies.  It  was  seen  two  or  three  hours  before  sunset, 
and  continued  visible  for  eight  successive  days.  The 
great  comet  of  1106,  described  as  an  object  of  ter- 
rific splendor,  was  seen  simultaneously  with  the  sun, 
and  in  close  proximity  to  it.  Dr.  Halley  supposed 
this  and  the  Julian  comet  to  have  been  previous 
visits  of  the  great  comet  of  1680.  In  the  year  1402 
two  comets  appeared, — one  about  the  middle  of 
February,  the  other  in  June, — both  of  which  were 
visible  while  the  sun  was  above  the  horizon.  One 
was  of  such  magnitude  and  brilliancy  that  the 
nucleus  and  even  the  tail  could  be  seen  at  midday. 
The  comet  of  1472,  one  of  the  most  splendid  re- 
corded in  history,  was  visible  in  full  daylight,  when 
nearest  the  earth,  on  the  21st  of  January.  This 


16  COMETS   AND    METEORS. 

comet,  according  to  Laugier,  moves  very  nearly  in 
the  plane  of  the  ecliptic,  its  inclination  being  less 
than  two  degrees.  Its  least  distance  from  our  globe 
was  only  3,300,000  miles.  The  comet  of  1532,  sup- 
posed by  some  to  be  identical  with  that  of  1661,  was 
also  visible  in  full  sunshine.  The  apparent  magni- 
tude of  its  nucleus  was  three  times  greater  than  that 
of  Jupiter.  The  comet  of  1577  was  seen  with  the 
naked  eye  by  Tycho  Brahe  before  sunset.  It  was 
by  observations  on  this  body  that  Aristotle's  doc- 
trine in  regard  to  the  origin,  nature,  and  distance 
of  comets  was  proved  to  be  erroneous.  It  was 
simultaneously  observed  by  Tycho  at  Oranienberg, 
and  Thaddeus  Hageeius  at  Prague;  the  points  of 
observation  being  more  than  400  miles  apart,  and 
nearly  on  the  same  meridian.  The  comet  was  found 
to  have  no  sensible  diurnal  parallax;  in  other  words, 
its  apparent  place  in  the  heavens  was  the  same  to 
each  observer,  which  could  not  have  been  the  case 
had  the  comet  been  less  distant  than  the  moon.  The 
comet  which  passed  its  perihelion  on  the  8th  of  No- 
vember, 1618,  was  distinctly  seen  by  Marsilius  when 
the  sun  was  above  the  horizon.  The  great  comet 
of  1744  was  seen  without  the  aid  of  a  glass  at  one 
o'clock  in  the  afternoon, — only  five  hours  after  its 
perihelion  passage.  The  diameter  of  this  body  was 
nearly  equal  to  that  of  Jupiter.  It  had  six  tails,  the 
greatest  length  of  which  was  about  30,000,000  miles, 
or  nearly  one-third  of  the  distance  of  the  earth  from 
the  sun.  The  spaces  between  the  tails  were  as  dark 
as  the  rest  of  the  heavens,  while  the  tails  themselves 
were  bordered  with  a  luminous  edging  of  great 
beauty. 


COMETS.  17 

The  great  comet  of  1843  was  distinctly  visible  to 
the  naked  eye,  at  noon,  on  the  28th  of  February. 
It  appeared  as  a  brilliant  body,  within  less  than  two 
degrees  from  the  sun.  This  comet  passed  its  peri- 
helion on  the  27th  of  February,  at  which  time  its 
distance  from  the  sun's  surface  was  only  about  one- 
fourth  of  the  moon's  distance  from  the  earth.  This 
is  the  nearest  approach  to  the  sun  ever  made  by  any 
known  comet.  The  velocity  of  the  body  in  peri- 
helion was  about  1,280,000  miles  an  hour,  or  nearly 
nineteen  times  that  of  the  earth  in  its  orbit.  The 
apparent  length  of  its  tail  was  sixty-five  degrees,  and 
its  true  length  150,000,000  miles.  The  first  comet 
of  1847,  discovered  by  Mr.  Hind,  was  also  seen  near 
the  sun  on  the  day  of  its  perihelion  passage.  That 
discovered  by  Klinkerfues  on  the  10th  of  June,  1853, 
and  which  passed  its  perihelion  on  the  1st  of  Sep- 
tember, was  seen  at  Olmutz  in  the  daytime,  August 
31,  when  only  twelve  degrees  from  the  sun.  After 
passing  its  perihelion,  it  was  again  observed,  at  noon, 
on  the  2d,  3d,  and  4th  of  September.  Finally,  the 
great  comet  of  1861  was  seen  before  sunset,  on 
Monday  evening,  July  1,  by  Rev.  Henry  W.  Ballan- 
tine,  of  Bloomington,  Indiana.  It  was  again  de- 
tected on  the  following  evening  just  as  the  sun  was 
in  the  horizon. 

Besides  the  thirteen  comets  which  we  have  enu- 
merated, at  least  four  others  have  been  seen  in 
the  daytime;  all,  however,  under  peculiar  circum- 
stances. Seneca  relates  that  during  a  great  solar 
eclipse,  63  years  before  our  era,  a  large  comet  was 
observed  not  far  from  the  sun.  "Philostorgius 
says  that  on  the  19th  of  July,  A.  D.  418,  when 

2* 


18  COMETS    AND    METEORS. 

the  sun  was  eclipsed  and  stars  were  visible,  a  great 
comet,  in  the  form  of  a  cone,  was  discovered  near 
that  luminary,  and  was  afterwards  observed  during 
the  nights/'*  The  comet  which  passed  its  peri- 
helion on  the  18th  of  November,  1826,  was  observed 
by  both  Gambart  and  Flaugergues  to  transit  the 
solar  disk, — the  least  distance  of  the  nucleus  from 
the  sun's  surface  being  about  2,000,000  miles.  The 
second  comet  of  1819  and  the  comet  of  1823  are 
both  known  in  like  manner  to  have  passed  between 
the  sun  and  the  earth.  Unfortunately,  however, 
the  transits  were  not  observed. 

A  few  cometary  orbits  are  hyperbolas,  more 
ellipses,  and  a  still  greater  number  parabolas. 
Comets  moving  in  ellipses  remain  permanently 
within  the  limits  of  solar  influence.  Others,  how- 
ever, visit  our  system  but  once,  and  then  pass  off«io 
wander  indefinitely  in  the  sidereal  spaces. 

Comets  of  known  periodicity. 

I.  Halley's  Comet. 

As  comets  are  subject  to  great  changes  of  appear- 
ance, one  can  never  be  identified  by  any  description 
of  its  magnitude,  brilliancy,  etc.,  at  the  time  of  a 
previous  return.  This  can  be  done  only  by  a  com- 
parison of  orbits.  If,  for  example,  we  find  the  ele- 
ments of  an  orbit  very  nearly  corresponding  in  every 
particular  with  those  of  a  former  comet,  there  is  a 
degree  of  probability,  amounting  almost  to  cer- 

*  Hind. 


19 

tainty,  that  the  two  are  identical.  Sir  Isaac  Newton, 
in  his  Principia,  published  shortly  after  the  appear- 
ance of  the  comet  of  1682,  explained  how  the  periods 
of  those  mysterious  visitors  might  thus  be  ascer- 
tained, thus  directing  the  attention  of  astronomers 
to  the  subject.  Dr.  Halley  soon  after  undertook  a 
thorough  discussion  of  all  the  recorded  cometary 
observations  within  his  reach.  In  the  course  of  his 
investigations  he  discovered  that  the  path  of  the 
comet  observed  by  Kepler  in  1607  coincided  almost 
exactly  with  that  of  the  one  which  passed  its  peri- 
helion in  1682.  Hence  he  concluded  that  they  were 
the  same.  He  found  also  that  the  comet  of  1531, 
whose  course  had  been  particularly  observed  by 
Apian,  moved  in  the  same  path.  The  interval 
between  the  consecutive  appearances  being  nearly 
76  years,  Halley  announced  this  as  the  time  of 
the  comet's  revolution,  and  boldly  predicted  its 
return  in  1758  or  1759.  The  law  of  universal  gravi- 
tation had  at  this  time  just  been  discovered  and 
announced.  But  although  its  application  to  the 
determination  of  planetary  and  cometary  perturba- 
tions had  not  been  developed,  Halley  was  well  aware 
that  the  attractive  influence  of  Jupiter  and  Saturn 
might  accelerate  or  retard  the  motion  of  the  cornet, 
so  as  to  produce  a  considerable  variation  in  its  period. 
During  the  interval  from  1682  to  1759,  the  applica- 
tion of  the  higher  mathematics  to  problems  in  physi- 
cal astronomy  had  been  studied  with  eminent  suc- 
cess. The  disturbing  effect  of  the  two  large  planets, 
Jupiter  and  Saturn,  was  computed  with  almost 
incredible  labor  by  Clairaut,  Lalande,  and  Madame 
Lepaute.  The  result  as  announced  by  Clairaut  to 


20  COMETS    AND    METEORS. 

the  Academy  of  Sciences  in  November,  1758,  was 
that  the  period  must  be  618  days  longer  than  that 
immediately  preceding,  and  that  the  comet  accord- 
ingly would  pass  its  perihelion  about  the  13th  of 
April,  1759.  It  was  stated,  however,  that,  being 
pressed  for  want  of  time,  they  had  neglected  certain 
quantities  which  might  somewhat  affect  the  result. 
The  comet,  in  fact,  passed  its  perihelion  in  March, 
within  less  than  a  month  of  the  predicted  time. 
When  it  is  considered  that  the  attraction  of  the 
earth  was  not  taken  into  the  account,  and  that 
Uranus,  whose  influence  must  have  been  sensible, 
had  not  then  been  discovered,  this  must  certainly 
be  regarded  as  a  remarkable  approximation. 

But  during  the  next  interval  of  76  years  the  theory 
of  planetary  perturbations  had  been  more  perfectly 
developed.  The  masses  of  Jupiter  and  Saturn  had 
been  determined  with  greater  accuracy,  and  Uranus 
had  been  added  to  the  known  members  of  the  plan- 
etary system.  A  nearer  approximation  to  the  exact 
time  of  the  comet's  perihelion  passage  in  1835  was 
therefore  to  be  expected.  Prizes  were  offered  by 
two  of  the  learned  societies  of  Europe — the  Academy 
of  Sciences  at  Turin,  and  the  French  Institute — for 
the  most  perfect  discussion  of  its  motions.  That  of 
the  former  was  awarded  to  Damoiseau, — that  of  the 
latter  to  Pontecoulant.  The  times  assigned  by  these 
distinguished  mathematicians  for  the  comet's  peri- 
helion passage  were  very  nearly  the  same,  and  dif- 
fered but  a  few  days  from  the  true  time.  Had  the 
present  received  mass  of  Jupiter  been  used  in  the 
calculations,  Pontecoulant,  it  is  believed,  would  not 
have  been  in  error  as  much  as  24  hours.  It  may  be 


HALLEY'S  COMET.  21 

proper  to  remark  that,  during  the  entire  period  from 
1759  to  1835,  the  position  of  Neptune  was  such  that 
it  could  produce  no  considerable  effect  on  the  motion 
of  the  comet. 

This  interesting  object  will  again  return  about 
1911. 

The  visit  of  1531  was  the  earliest  that  Halley  suc- 
ceeded in  determining  with  any  degree  of  certainty. 
Peter  Apian,  by  whom  it  was  at  that  time  observed, 
was  the  first  European  to  ascertain  the  fact  that,  as 
a  general  thing,  the  tails  of  comets  are  turned  from 
the  sun.*  To  confirm  this  discovery,  he  carefully 
followed  the  body  in  its  progress  through  the  con- 
stellations. By  means  of  his  recorded  observations 
Halley  was  enabled  to  identify  this  comet  with  that 
of  1607  and  1682.  The  great  comet  of  1456  he  con- 
jectured to  be  the  same,  from  the  date  of  its  appear- 
ance. Pingre  subsequently  confirmed  this  -suspicion 
by  a^  careful  examination  of  the  few  trustworthy 
records  that  could  be  collected  from  the  writers  of 
that  period. 

From  the  earlier  descriptions  of  this  comet  we 
infer  that  its  brilliancy  is  gradually  diminishing.  In 
1456  its  tail,  which  was  slightly  curved  like  a  sword 
or  sabre,  extended  two-thirds  of  the  distance  from  the 
horizon  to  the  zenith.  The  appearance  of  such  an 
object,  in  a  grossly  superstitious  age,  excited  through- 
out Europe  the  utmost  consternation.  The  Moslems 
had  just  taken  Constantinople,  and  were  threatening 

*  The  Chinese,  however,  as  appears  from  Blot's  researches,  had 
observed  the  same  fact  700  years  earlier.  See  Humboldt's  Cosmos, 
vol.  iv.  (Bohn's  ed.),  p.  544. 


22  COMETS   AND    METEORS. 

to  advance  westward  into  Europe.  Pope  Calix- 
tus  III.,  regarding  the  comet  as  confederate  with 
the  Turk,  ordered  prayers  to  be  offered  three  times 
a  day  for  deliverance  from  both.  The  alarm,  how- 
ever, was  of  short  duration.  Within  ten  days  of  its 
appearance  the  comet  reached  its  perihelion.  Re- 
ceding from  the  sun,  the  sword-like  form  began  to 
diminish  in  brilliancy  and  extent;  and  finally,  to  the 
great  relief  of  Europe,  it  entirely  disappeared. 

The  perihelion  passage  of  1456  was,  until  recently, 
the  earliest  known.  It  was  shown  by  Laugier,  how- 
ever, in  1843,  that  among  the  notices  of  comets  ex- 
tracted by  Edward  Biot  from  the  Chinese  records, 
were  observations  of  a  body  in  1378,  which  was  un- 
doubtedly the  comet  of  Halley.  Further  researches 
among  these  annals  enabled  the  same  astronomer  to 
recognize  two  ancient  returns,  one  in  760,  the  other 
in  451.  Still  more  recently  the  distinguished  Eng- 
lish astronomer,  Mr.  Hind,  has  traced  back  the  re- 
turns to  the  year  11  B.C.  He  remarks,  however, 
that  previous  to  that  epoch,  "the  Chinese  descrip- 
tions of  comets  are  too  vague  to  aid  us  in  tracing 
any  more  ancient  appearances,"  and  that  "  European 
writers  of  these  remote  times  render  us  no  assist- 
ance." Let  us  now  inquire  whether  the  comet  had 
probably  made  any  former  approach  to  the  sun  in 
an  orbit  nearly  identical  with  the  present.  It  is 
well  known  that  the  modern  period  of  this  body  is 
considerably  less  than  the  ancient.  Thus,  the  mean 
period  since  A.D.  1456  has  been  75.88  years;  while 
from  11  B.C.  to  1456  A.D.  it  was  77.27  years.  In  de- 
termining the  approximate .  dates  of  former  returns, 
the  ancient  period  should  evidently  be  employed. 


HALLEY'S  COMET.  23 

,  it  is  a  remarkable  fact  that  of  more  than  70 
comets,*  or  objects  supposed  to  be  comets,  whose 
appearance  was  recorded  during  the  six  centuries 
immediately  preceding  the  year  11  B.C.,  but  one  — 
that  of  166  B.C.  —  was  observed  at  a  date  correspond- 
ing nearly  to  that  of  a  former  return  of  Halley's 
comet.  Of  this  object  it  is  merely  recorded  that  "  a 
torch  was  seen  in  the  heavens."  Whether  this  was 
a  comet  or  some  other  phenomenon,  it  is  impossible 
to  determine.  But  as  the  comet  of  Halley  was 
more  brilliant  in  ancient  than  in  modern  times,  it 
seems  highly  improbable  that  seven  consecutive  re- 
turns of  so  conspicuous  an  object  should  have  been 
unrecorded,  especially  as  twelve  comets  per  century  f 
were  observed  during  the  same  period.  It  would 
appear,  therefore,  that  the  perihelion  passage  of 
11  B.C.  was  in  fact  the  first  ever  made  by  the  comet, 
or  at  least  the  first  in  an  orbit  nearly  the  same  as 
the  present. 

The  motion  of  Halley's  comet  is  retrograde.  The 
point  of  its  nearest  approach  to  the  sun  is  situated 
within  the  orbit  of  Yenus.  Its  greatest  distance 
from  the  centre  of  the  system  is  nearly  twice  that 
of  Uranus,  or  36  times  that  of  the  earth.  The 
comet  is,  consequently,  subject  to  great  changes  of 
temperature.  When  nearest  the  sun  its  light  and 
heat  are,  almost  four  times  greater  than  the  earth's; 
when  most  remote,  they  are  1200  times  less.  In 
the  former  position,  the  sun  would  appear  much 
larger  than  to  us;  in  the  latter,  his  apparent  di- 


*  See  the  Catalogues  of  Chambers  and  Williams. 
f  The  average  number. 


24  COMETS    AND    METEORS. 

ameter  would  not  greatly  exceed  that  of  Jupiter,  as 
viewed  from  the  earth.  It  would  be  difficult  to  con- 
jecture what  the  consequences  might  be,  were  our 
planet  transported  to  either  of  these  extremes  of 
the  cometary  path.  In  the  perihelion,  the  waters 
of  the  ocean  would  undoubtedly  be  reduced  to  a 
state  of  vapor;  in  the  aphelion,  they  would  be 
solidified  by  congelation. 

II.  Encke's  Comet. 

It  was  formerly  supposed  that  all  comets  have 
their  aphelia  far  beyond  the  limits  of  the  planetary 
system.  In  1818,  however,  a  small  comet  was  dis- 
covered by  Pons,  the  orbit  of  which  was  subse- 
quently found  to  be  wholly  interior  to  that  of  Ju- 
piter. Its  elements  were  presented  by  Bouvard,  in 
1819,  to  the  Board  of  Longitude  at  Paris.  The 
form  and  position  of  the  orbit  were  immediately 
found  to  correspond  with  those  of  a  comet  observed 
by  several  astronomers  in  1805.  The  different  ap- 
pearances were  consequently  regarded  as  returns  of 
the  same  body.  Its  elliptic  orbit  was  calculated  by 
Encke,  who  found  its  period  to  be  only  about  three 
years  and  four  months.  Its  perihelion  is  within  the 
orbit  of  Mercury;  its  aphelion,  between  the  as- 
teroids and  the  orbit  of  Jupiter.  . 

Encke's  comet  is  invisible  to  the  naked  eye,  ex- 
cept in  very  favorable  circumstances;  it  has  no  tail; 
its  motion,  like  that  of  the  planets,  is  from  west 
to  east;  and  its  orbit  is  inclined  about  13°  to  the 
ecliptic. 

A  comparison  of  the  successive  periods  of  this 


BIELA'S  COMET.  25 

interesting  object  has  led  to  the  discovery  that  its 
time  of  revolution  is  gradually  diminishing;  a  fact 
regarded  by  Encke  and  other  astronomers  as  indi- 
cating the  existence  of  an  ethereal  medium. 

Ill,  Biela's  Comet. 

The  discovery  of  Encke's  comet  of  short  period 
was  followed,  in  1826,  by  that  of  another,  whose 
revolution  is  completed  in  about  six  years  and  eight 
months.  It  was  observed  on  the  27th  of  February, 
by  M.  Biela,  an  Austrian  officer;  accordingly  it 
has  since  been  known  as  Biela  s  comet.  On  com- 
puting its  elements  and  comparing  them  with  those 
of  former  comets,  it  was  found  to  have  been  ob- 
served in  1772  and  1805.  Damoiseau  having  cal- 
culated the  dimensions  of  the  comet's  elliptic  path 
and  the  time  of  its  return,  announced  as  the  result 
of  his  computations  the  remarkable  fact  that  the 
orbits  of  the  earth  and  cornet  intersect  each  other, 
and  that  the  comet  would  cross  the  earth's  path  on 
the  29th  of  October,  1832.  This  produced  no  little 
alarm  among  the  uneducated,  especially  in  France. 
Even  some  journalists  are  said  to  have  predicted 
the  destruction  of  our  globe  by  a  collision  with  the 
comet.  When  the  latter,  however,  passed  the  point 
of  intersection  at  the  predicted  time,  the  earth  was 
at  a  distance  of  50,000,000  miles. 

At  the  return  of  1845-6,  Biela's  comet  exhibited 
a  most  remarkable  appearance.  Instead  of  a  single 
comet,  it  appeared  as  two  distinct  bodies  moving 
together  side  by  side,  at  a  distance  from  each  other 
somewhat  less  than  that  of  the  moon  from  the  earth. 

3 


ZO  COMETS   AND   METEORS. 

Astronomers,  anxious  to  determine  whether  the 
eometary  fragments  had  continued  separate  during 
an  entire  revolution,  awaited  the  next  return  with 
no  ordinary  interest.  The  two  bodies  appeared  at 
the  predicted  time  (September,  1852);  their  distance 
apart  having  increased  to  1,250,000  miles.  In  1859 
the  comet,  on  account  of  its  proximity  to  the  sun, 
entirely  escaped  detection.  At  the  return  in  1865-6 
the  position  of  the  object  was  quite  favorable  for 
observation,  yet  the  search  of  astronomers  was 
again  unsuccessful.  In  1872  the  body  escaped  de- 
tection, both  in  Europe  and  America.  One  frag- 
ment was  seen,  however,  at  Madras,  India,  on  the 
mornings  of  the  2d  and  3d  of  December, — several 
weeks  after  its  perihelion  passage.  The  comet's 
non-appearance  in  1866  and  its  greatly  diminished 
magnitude  in  1872  leave  no  room  to  doubt  its  pro- 
gressive dissolution.  This  subject  will  again  be  re- 
ferred to  in  discussing  the  phenomena  of  meteoric 
showers. 

IV.  Faye's  Comet. 

On  the  22d  of  November,  1843,  M.  Faye,  of  the 
Paris  Observatory,  discovered  a  comet,  which  was 
shown  by  Dr.  Goldschmidt  to  revolve  in  an  elliptic 
orbit,  the  perihelion  of  which  is  exterior  to  the 
orbit  of  Mars,  and  the  aphelion  immediately  be- 
yond that  of  Jupiter.  The  eccentricity  is,  therefore, 
less  than  that  of  any  other  comet  previously  dis- 
covered. Its  period  is  about  7  years  and  5  months. 

It  is  possible  that  a  comet  moving  in  a  parabola 
or  hyperbola,  with  the  sun  in  the  focus,  may  be 
thrown  into  an  elliptic  orbit  by  the  disturbing  in- 


27 

fluence  of  Jupiter  or  one  of  the  other  large  planets. 
The  celebrated  Leverrier  undertook  to  determine 
whether  the  comet  of  Faye  had  in  this  manner 
been  recently  fixed  as  a  permanent  member  of  the 
solar  system.  He  found  that  it  could  not  have  been 
so  introduced  since  1747,  and,  consequently,  that  it 
must  have  completed  at  least  thirteen  revolutions 
before  its  discovery. 

This  comet  has  been  observed  at  each  return 
from  1843  to  the  present  time. 

V.  De  Vico's  Comet. 

On  the  22d  of  August,  1844,  De  Vico,  of  Rome, 
discovered  a  comet  whose  orbit  is  included  between 
those  of  the  earth  and  Jupiter.  Its  period  is  1996 
days,  or  about  5J  years.  This  body,  from  some 
cause, — perhaps  a  gradual  dissolution, — has  not 
been  observed  at  any  subsequent  return. 

VI.  Brorsen's  Comet. 

On  the  26th  of  February,  1846,  Mr.  Brorsen,  of 
Kiel,  discovered  a  faint  comet,  the  mean  distance 
and  period  of  which  are  almost  identical  with  those 
of  De  Vico's.  This  comet  was  not  observed  during 
the  perihelion  passage  of  1851,  on  account  of  its 
unfavorable  position  with  respect  to  the  sun.  It 
has,  however,  been  subsequently  detected. 

VII.  D'Arresf  s  Comet. 

Dr.  D'Arrest  discovered  a  comet  on  the  27th  of 
June,  1851,  which  was  soon  found  to  move  in  an 


28  COMETS   AND   METEORS. 

elliptic  orbit,  with  a  period  of  about  6J  years.  It 
entirely  escaped  observation,  both  in  Europe  and 
America,  during  its  perihelion  passage  in  1857.  It 
was  observed,  however,  at  the  Cape  of  Good  Hope. 
Its  invisibility  in  1864  was  due  to  its  unfavorable 
position.  At  its  return  in  1870,  it  was  first  seen  on 
the  31st  of  August,  by  Dr.  Winnecke,  of  Carlsruhe. 

VIII.  Turtle's  Comet, 

A  faint  telescopic  comet  was  discovered  at  the 
Observatory  of  Harvard  College,  on  the  evening  of 
January  4,  1858,  by  Mr.  H.  P.  Tuttle.  The  same 
body  was  independently  found  one  week  later  by 
Dr.  Bruhns,  of  Berlin.  From  observations  made 
at  Cambridge,  Massachusetts,  and  Ann  Arbor, 
Michigan,  its  elements  were  soon  computed  by  dif- 
ferent astronomers;  the  result  in  each  case  coin- 
ciding so  closely  with  the  elements  of  the  second 
comet  of  1790,  as  to  place  its  identity  wholly  beyond 
doubt.  Its  period  is  nearly  13  years  and  8  months. 
It  had  returned,  therefore,  without  detection,  in  the 
years  1803,  1817,  1831,  and  1844.  On  its  approach 
to  perihelion  in  1871,  it  was  first  detected  by  M. 
Borelly,  of  Marseilles. 

IX,  Winnecke's  Comet. 

The  second  comet  of  1858  was  discovered  on  the 
8th  of  March,  by  Dr.  Winnecke,  of  Bonn.  This 
proved  to  be  identical  with  the  third  comet  of  1819, 
whose  period  was  computed  by  Encke  to  be  about 
5J  years.  It  had  therefore  returned  uuperceived 


29 


no  less  than  six  times  between  1819  and  1858.  At 
its  return  in  1863  it  again  escaped  detection.  The 
perihelion  passage  of  1869  was  made  on  the  30th  of 
June.  The  comet  was  seen  as  early  as  April  13, 
and,  after  passing  the  sun,  as  late  as  October  11. 
"  Schonfeld  states  that  in  part  of  April  and  May  it 
appeared  to  have  not  one,  but  several,  centres  of 
condensation,  and  Yogel  says  that,  in  the  beginning 
of  June,  ib  had  a  much  greater  resemblance  to  a 
star-cluster  than  to  a  nebula."  This  phenomenon, 
it  may  be  remarked,  bore  a  striking  resemblance  to 
the  appearances  observed  in  the  comets  of  389, 
1618,  and  1661. 

X.  Tempers  Comet. 

On  the  19th  of  December,  1865,  M.  Tempel,  of 
Marseilles,  discovered  a  small  comet,  which  con- 
tinued visible  four  weeks,  passing  its  perihelion  Jan- 
uary 11,  1866.  Dr.  Oppolzer,  of  Vienna,  after  a 
careful  determination  of  its  elements,  announced 
the  interesting  fact  that  its  orbit  very  nearly  inter- 
sects those  of  the  earth  and  Uranus;  the  perihelion 
being  situated  immediately  within  the  former,  and 
the  aphelion  a  short  distance  exterior  to  the  latter. 
The  period,  according  to  the  same  astronomer,  is 
33  years  and  65  days.  The  identity  of  this  comet 
with  that  of  1366  was  suggested  by  Professor  H.  A. 
Newton  soon  after  its  appearance, — a  suggestion 
which  subsequent  research  has  strongly  corrobo- 
rated. It  is  also  highly  probable  that  the  comet 
observed  in  China,  September  29,  1133,  was  a  for- 
mer return  of  the  same  body.  In  1366  it  was  con- 

3 


30  COMETS   AND    METEORS. 

spicuous  to  the  naked  eye,  while  in  1866  it  was 
wholly  invisible  without  a  telescope, — a  fact  indic- 
ative of  its  gradual  dissolution.  The  connection  of 
this  comet  with  the  meteors  of  November  14  will 
be  elsewhere  considered. 

XI.  The  Second  Comet  of  1867. 

Another  comet  of  short  period  was  discovered  by 
M.  Tempel  on  the  3d  of  April,  1867.  Its  orbit  is 
the  least  eccentric  of  all  known  comets:  the  peri- 
helion being  exterior  to  the  orbit  of  Mars;  the 
aphelion  interior  to  that  of  Jupiter.  Its  motion  is 
direct,  and  it  completes  a  revolution  in  5  years  and 
8  months. 


CHAPTER   III. 


COMETS   WHOSE    ELEMENTS    INDICATE   PERIODICITY,  BUT 
WHOSE   RETURNS    HAVE   NOT    BEEN    RECOGNIZED. 

I.  The  Group  whose  periods  are  nearly  equal  to  that  of 

Uranus. 

SINCE  the  commencement  of  the  present  century 
five  comets  have  been  discovered,  which  form,  with 
Halley's,  an  interesting  and  remarkable  group. 
The  first  of  these  was  detected  by  Pons,  on  the  20th 
of  July,  1812  ;  the  second  by  Olbers,  on  the  6th  of 
March,  1815;  the  third  by  De  Yico,  on  the  28th  of 
February,  1846;  the  fourth  by  Brorsen,  on  the  20th 
of  July,  1847;  and  the  last  by  Westphal,  on  the 
27th  of  June,  1852.  The  periods  of  these  bodies 
are  all  nearly  equal,  ranging  from  68  to  76  years; 
their  eccentricities  are  not  greatly  different ;  the 
motions  of  all,  except  that  of  Halley's,  are  direct ; 
and  the  distances  of  their  aphelia  are  somewhat 
greater  than  Neptune's  distance  from  the  sun.  Of 
this  group,  the  comets  of  1812  and  1846  seem 
worthy  of  special  notice.  The  former  became  vis- 
ible to  the  naked  eye  shortly  after  its  discovery,  and 
each  continued  visible  about  ten  weeks.  Their 
elements  are  as  follows  : 


Perihelion  Passage. 

Long,  of 
Perih'n. 

Long,  of 
A.  Node. 

Incl. 

Peri'n 
Dist. 

Eccen- 
tricity. 

Pe- 
riod. 

Direc- 
tion. 

Com- 
puter. 

1812,  Sept.  15d.7/i. 

92°  51' 

253°  33' 

73°  57' 

0.7771 

0.94454 

70.68y 

D 

Encke. 

1846,  Mar.    5d.l2h. 

90°  31' 

77°  37' 

85°  6' 

O.C637 

0.96224 

73.715 

D 

Peirce. 

32 


COMETS   AND    METEORS. 


The  wonderful  similarity  of  these  elements,  except 
in  the  longitude  of  the  ascending  node,  is  at  once 
apparent.  It  will  also  be  noticed  that  the  longitude 
of  the  descending  node  of  the  latter  is  very  nearly 
coincident  with  that  of  the  ascending  node  of  the 
former.  These  remarkable  coincidences  are  pre- 
sented to  the  eye  in  the  following  diagram,  where 

Fig.  3. 


the  dotted  ellipse  represents  the  orbit  of  the  comet 
of  1812,  and  the  continuous  curve  that  of  the  comet 
of  1846. 


COMETS   WHOSE    ELEMENTS    INDICATE    PERIODICITY.       33 

It  is  infinitely  improbable  that  these  coincidences 
should  be  accidental;  they  point  undoubtedly  to  a 
common  origin  of  the  two  bodies. 

According  to  the  theory  now  generally  accepted, 
comets  enter  the  solar  system  ab  extra,  move  in 
parabolas  or  hyperbolas  around  the  sun,  and,  if  un- 
disturbed by  the  planets,  pass  off  beyond  the  limits 
of  the  sun's  attraction,  to  be  seen  no  more.  If  in 
their  motion,  however,  they  approach  very  near  any 
of  the  larger  planets,  their  direction  is  changed  by 
planetary  perturbation, — their  orbits  being  some- 
times transformed  into  ellipses.  The  new  orbits  of 
such  bodies  would  pass  very  nearly  through  the 
points  at  which  their  greatest  perturbation  occurred ; 
and  accordingly  we  find  that  the  aphelia  of  a  large 
proportion  of  the  periodic  comets  are  near  the  orbits 
•of  the  major  planets.  "I  admit,"  says  M.  Hoek, 
"  that  the  orbits  of  comets  are  by  nature  parabolas 
or  hyperbolas,  and  that  in  the  cases  when  elliptical 
orbits  are  met  with,  these  are  occasioned  by  planet- 
ary attractions,  or  derive  their  character  from  the 
uncertainty  of  our  observations.  To  allow  the  con- 
trary would  be  to  admit  some  comets  as  permanent 
members  of  our  planetary  system,  to  which  they 
o  ught  to  have  belonged  since  its  origin,  and  so  to 
assert  the  simultaneous  birth  of  that  system  and  of 
these  comets.  As  for  me,  I  attribute  to  these  a 
primitive  wandering  character.  Traveling  through 
space,  they  move  from  one  star  to  another  in  order 
to  leave  it  again,  provided  they  do  not  meet  any 
obstacle  that  may  force  them  to  remain  in  its 
vicinity.  Such  an  obstacle  was  Jupiter,  in  the 
neighborhood  of  our  sun,  for  the  comets  of  Lexell 


34  COMETS   AND   METEORS. 

and  Brorsen,  and  probably  for  the  greater  part  of 
periodical  comets ;  the  other  part  of  which  may  be 
indebted  for  their  elliptical  orbits  to  the  attractions 
of  Saturn  and  the  remaining  planets. 

"  Generally,  then,  comets  come  to  us  from  some 
star  or  other.  The  attraction  of  our  sun  modifies 
their  orbit,  as  had  been  done  already  by  each  star 
through  whose  sphere  of  attraction  they  had  passed. 
We  can  put  the  question  if  they  come  as  single 
bodies  or  united  in  systems." 

The  conclusion  of  this  astronomer's  interesting 
discussion  is  that — 

"  There  are  systems  of  comets  in  space  that  are  broken 
up  by  the  attraction  of  our  sun,  and  whose  members  attain, 
as  isolated  bodies,  the  vicinity  of  the  earth  during  a  course 
of  several  years."* 

In  the  researches  here  referred  to,  it  is  shown  by 
Professor  Hoek  that  the  comets  of  1860  III.,  1863  L, 
and  1863  IV.  formed  a  group  in  space  previous  to 
their  entrance  into  our  system.  The  same  fact  has 
also  been  demonstrated  in  regard  to  other  comets 
which  need  not  here  be  specified.  Now,  the  comets 
of  1812  and  1846  IV.  have  their  aphelia  near  the 
orbit  of  Neptune,  and  hence  the  original  parabolas 
in  which  they  moved  were  probably  transformed 
into  ellipses  by  the  'perturbations  of  that  planet. 
Before  entering  the  solar  domain,  they  were  doubt- 
less members  of  a  cometary  system.  Passing 
Neptune  near  the  same  time,  and  at  some  distance 
from  each  other,  their  different  relative  positions 
with  regard  to  the  disturbing  body  may  account 

*  Monthly  Notices  of  the  K.  A.  S.,  vol.  xxv.,  p.  243. 


COMETS   OF   THE   JOVIAN   GROUP.  35 

for   the  slight  differences  in  the  elements  of  their 
orbits. 

Comets  of  the  Jovian  Group. 

Besides  the  eight  comets  enumerated  in  Chapter 
II.  whose  aphelia  are  in  the  vicinity  of  Jupiter's  orbit, 
five  others  have  been  observed  which  belong  ap- 
parently to  the  same  cluster.  These  are  the  comets 
of  1585, 1743  L,  1766  II.,  1783,  and  1819 IY.  "  The 
fact  that  these  comets  have  not  been  re-observed  on 
their  successive  returns  through  perihelion  may  be 
explained  either  by  the  difficulty  of  observing  them, 
owing  to  their  unfavorable  positions,  and  to  the 
circumstances  of  observers  not  expecting  their  re- 
appearance, their  periodic  character  not  being  then 
suspected,  or  because  they  may  have  been  thrown 
by  the  disturbing  action  of  the  larger  planets  into 
orbits  such  as  to  keep  them  continually  out  of  the 
range  of  view  of  terrestrial  observers."* 

LexelPs  comet  of  1770  is  the  most  remarkable 
instance  known  of  the  change  produced  in  the 
orbits  of  these  bodies  by  planetary  attraction.  This 
comet  passed  so  near  Jupiter  in  1779  that  the  attrac- 
tion of  the  latter  was  200  times  greater  than  that  of 
the  sun.  The  consequence  was  that  the  comet, 
whose  mean  distance  corresponded  to  a  period  of 
5  J  years,  was  thrown  into  an  orbit  so  entirely  differ- 
ent that  it  has  never  since  been  visible. 

*  Dr.  Lardner. 


36  COMETS  AND  METEORS.  ' 

PETERS'  COMET. 

A  telescopic  comet  was  discovered  by  Dr.  Peters 
on  the  26th  of  June,  1846,  which  continued  to  be 
observed  till  the  21st  of  July.  Its  period,  according 
to  the  discoverer,  is  about  13  years,  and  its  aphelion, 
like  that  of  Tuttle's  comet,  is  in  the  vicinity  of 
Saturn's  orbit.  It  was  expected  to  return  in  1859, 
and  again  in  1872,  but  each  time  escaped  detection, 
owing  probably  to  the  fact  that  its  position  was  un- 
favorable for  observation. 

STEPHAN'S  COMET  (1867  L). 

In  January,  1867,  M.  Stephan,  of  Marseilles,  dis- 
covered a  new  comet,  the  elements  of  which,  after 
two  months'  observations,  were  computed  by  Mr. 
G.  M.  Searle,  of  Cambridge,  Massachusetts.  The 
perihelion  of  this  body  is  near  the  orbit  of  Mars  ;  its 
aphelion  near  that  of  Uranus, — the  least  distance  of 
the  orbits  being  about  2,000,000  miles.  The  present 
form  of  the  cometary  path  is  doubtless  due  to  the 
disturbing  action  of  Uranus.  The  comet  completes 
its  revolution  in  33.62  years;  consequently  (as  has 
been  pointed  out  by  Mr.  J.  R.  Hind)  five  of  its 
periods  are  almost  exactly  equal  to  two  periods  of 
Uranus.  The  next  approximate  appulse  of  the  two 
bodies  will  occur  in  1985,  when  the  form  of  the 
comet's  orbit  may  be  sensibly  modified. 

ELLIPTIC  COMETS  WHOSE  APHELIA  ARE  AT  A  MUCH 
GREATER  DISTANCE  THAN  NEPTUNE'S  ORBIT. 

In  October,  1097,  a  comet  was  seen  both  in  Eu- 
rope and  China,  which  was  noted  for  the  fact  of  its 


THE    GREAT    COMET    OF    1858.  37 

having  two' distinct  tails,  making  with  each  other 
an  angle  of  about  40°.  From  a  discussion  of  the 
Chinese  observations  (which  extended  through  a 
longer  period  than  the  European),  Laugier  con- 
cluded that  this  body  is  identical  with  the  third 
comet  of  1840,  which  was  discovered  by  G-alle  on 
the  6th  of  March.  If,  therefore,  it  has  made  no 
intermediate  return  without  being  observed,  it  must 
have  a  period  of  about  743  years.  Jt  is  also  highly 
probable,  from  the  similarity  of  elements,  that  the 
comet  which  passed  its  perihelion  on  the  5th  of  June, 
1845,  was  a  reappearance  of  the  comet  of  1596, — the 
period  of  revolution  being  249  years.  The  elements 
of  the  great  comet  of  1843  are  somewhat  uncertain. 
There  is  a  probability,  however,  of  the  identity  of 
this  body  with  the  comet  of  1668.  This  would  make 
the  period  175  years.  The  third  comet  of  1862  is 
especially  interesting  from  its  connection  with  the 
August  meteors.  Its  period,  according  to  Dr.  Op- 
polzer,  is  121J  years. 

THE  GREAT  COMET  OF  1858 

was  one  of  the  most  remarkable  in  the  nineteenth 
century.  It  was  discovered  on  the  2d,of  June,  by 
Donati,  of  Florence,  and  first  became  visible  to  the 
naked  eye  about  the  last  of  August.  The  comet 
attained  its  greatest  brilliancy  about  the  10th  of 
October,  when  its  distance  from  the  earth  was 
50,000,000  miles.  The  length  of  its  tail  somewhat 
exceeded  this  distance.  If,  therefore,  the  comet  had 
been  at  that  time  directly  between  the  sun  and  the 

4 


38  COMETS    AND    METEORS. 

earth,  the  latter  must  have  been  enveloped  for  a 
number  of  hours  in  the  cometic  matter. 

The  observations  of  this  comet  during  a  period  of 
five  months  enabled  astronomers  to  determine  the 
elements  of  its  orbit  within  small  limits  of  error.  It 
completes  a  revolution,  according  to  Newcomb,  in 
1854  years,  in  an  orbit  somewhat  more  eccentric 
than  that  of  Halley's  comet.  It  will  not  return 
before  the  38th.  century,  and  will  only  reach  its 
aphelion  about  the  year  2800.  Its  motion  per  second 
when  nearest  the  sun  is  36  miles;  when  most  remote, 
only  234  yards. 


CHAPTEK    IV. 

OTHER   REMARKABLE    COMETS. 

IT  remains  to  describe  some  of  the  most  remark- 
able comets  of  which  we  have  any  record,  but  of 
which  we  have  no  means  of  determining  with  cer- 
tainty whether  they  move  in  ellipses,  parabolas,  or 
hyperbolas. 

In  the  year  466  B.C.,  a  large  comet  appeared  sim- 
ultaneously with  the  famous  fall  of  meteoric  stones 
near  ^Egospotamos.  The  former  was  supposed 
by  the  ancients  to  have  had  some  agency  in  pro- 
ducing the  latter  phenomenon.  Another  of  extra- 
ordinary magnitude  appeared  in  the  year  373  B.C. 
This  comet  was  so  bright  as  to  throw  shadows,  and 
its  tail  extended  one-third  of  the  distance  from  the 
horizon  to  the  zenith.  The  years  156, 136, 130,  and 
48,  before  our  era,  were  also  signalized  by  the  ap- 
pearance of  very  large  comets.  The  apparent  mag- 
nitude of  the  first  of  these  is  said  to  have  equaled 
that  of  the  sun  itself;  while  its  light  was  sufficient 
to  diminish  sensibly  the  darkness  of  the  night. 
The  second  is  said  to  have  filled  a  fourth  part  of 
the  celestial  hemisphere.  The  comet  of  130  B.C., 
sometimes  called  the  comet  of  Mithridates,  because 
of  its  appearance  about  the  time  of  his  birth,  is  said 
to  have  rivaled  the  sun  in  splendor. 

In  A.D.  178  a  large  comet  was  visible  during  a 

39 


40  COMETS   AND    METEORS. 

period  of  nearly  three  months.  Its  nucleus  had  a 
remarkably  red  or  fiery  appearance,  and  the  great- 
est length  of  its  tail  exceeded  60°.  The  most  bril- 
liant comets  of  the  sixth  century  were  probably 
those  of  531  and  582.  The  train  of  the  latter,  as 
seen  in  the  west  soon  after  sunset,  presented  the 
appearance  of  a  distant  conflagration. 

Great  comets  appeared  in  the  years  975,  1264, 
and  1556.  Of  these,  the  comet  of  1264  had  the 
greatest  apparent  magnitude.  It  was  first  seen 
early  in  July,  and  attained  its  greatest  brilliancy  in 
the  latter  part  of  August,  wrhen  its  tail  was  100°  in 
length.  It  disappeared  on  the  3d  of  October,  about 
the  time  of  the  death  of  Pope  Urban  IV.,  of  which 
event  the  comet,  in  consequence  of  this  coincidence, 
was  considered  the  precursor.  These  comets,  on 
account  of  the  similarity  of  their  elements,  were 
believed  by  many  astronomers  to  be  the  same,  and 
to  have  a  period  of  about  300  years.  In  the  case  of 
identity,  however,  another  reappearance  should 
have  occurred  soon  after  the  middle  of  the  nineteenth 
century.  As  no  such  return  was  observed,  we  may 
conclude  that  the  comets  were  not  the  same,  and 
that  their  periods  are  wholly  unknown. 

The  comet  discovered  on  the  10th  of  November, 

1618,  was  one  of  the  largest  in  modern  times;  its 
tail  having  attained  the  extraordinary  length  of 
104°.  The  comet  of  1652,  so  carefully  observed  by 
Hevelins,  almost  equaled  the  moon  in  apparent 
magnitude.  It  shone,  however,  with  a  lurid,  dismal 
light.  The  tail  of  the  comet  of  1680  was  90°  in 
length.  This  body  is  also  remarkable  for  its  near 

approach  to  the  sun ;  its  least  distance  from  the 


OTHER  REMARKABLE  COMETS.          41 

solar  surface  having  been  only  147,000  miles.  It 
will  always  be  especially  memorable,  however,  for 
having  furnished  Newton  the  data  by  means  of 
which  he  first  showed  that  comets  in  their  orbital 
motions  are  governed  by  the  same  principle  that 
regulates  the  planetary  revolutions. 

Of  all  the  comets  which  appeared  during  the  eight- 
eenth century,  that  which  passed  its  perihelion  on  the 
7th  of  October,  1769,  had  the  greatest  apparent  mag- 
nitude. It  was  discovered  by  Messier  on  the  8th  of 
August,  and  continued  to  be  observed  till  the  1st  of 
December.  On  the  llth  of  September  the  length 
of  its  tail  was  97°.  The  comet  discovered  on  the 
26th  of  March,  1811,  is  in  some  respects  the  most 
remarkable  on  record.  It  was  observed  during  a 
period  of  16  months  and  22  days, — the  longest 
period  of  visibility  known.  On  account  of  its  situ- 
ation with  respect  to  the  earth,  the  apparent  length 
of  its  tail  was  much  less  than  that  of  some  other 
cornets  ;  its  true  length,  however,  was  at  one  time 
120,000,000  miles;  and  Sir  William  Herschel  found 
that  on  the  12th  of  October  the  greatest  circular 
section  of  the  tail  was  15,000,000  miles  in  diameter. 
The  same  astronomer  found  the  diameter  of  the 
head  of  the  comet  to  be  127,000  miles,  and  that  of 
the  envelope  at  least  643,000.  As  a  general  thing, 
the  length  of.  a  comet-train  increases  very  rapidly 
as  the  body  approaches  the  sun.  But  the  perihelion 
distance  of  the  comet  of  1811  was  considerably 
greater  than  the  distance  of  the  earth  from  the 
sun ;  while  its  nearest  approach  to  the  earth  was 
110,000,000  miles.  Its  true  magnitude,  therefore, 

has  probably  not  been  surpassed  by  any  other  ob- 

4* 


42  COMETS    AND    METEORS. 

served ;  and  had  its  perihelion  been  very  near  the 
sun,  it  must  have  exhibited  an  appearance  of  terrific 
grandeur.  This  comet  has  an  elliptic  orbit,  and  its 
period,  according  to  Argelander,  is  3065  years. 

The  great  comet  of  1861  was  discovered  on  the 
13th  of  May,  by  Mr.  John  Tebbut/Jr.,  of  New 
South  Wales.  In  this  country,  as  well  as  in  Eu- 
rope, it  was  first  generally  observed  on  the  evening 
of  June  30, — 19  days  after  its  perihelion  passage. 
Sir  John  Herschel,  who  observed  it  in  Kent,  Eng- 
land, remarks  that  it  far  exceeded  in  brilliancy  any 
comets  he  had  ever  seen,  not  excepting  those  of 
1811  and  1858.  According  to  Father  Secchi,  of  the 
Collegio  Romano,  the  length  of  its  tail  was  118°. 
This,  with  a  single  exception,*  is  the  greatest  on 
record.  The  computed  orbit  is  elliptical ;  the 
period,  419  years. 

*  The  tail  of  the  first  comet  of  1865  (observed  in  the  Southern 
Hemisphere)  attained  the  unprecedented  length  of  150°. — M.  N. 
R.  A.  S.,  vol.  xxv.,  p.  220. 


CHAPTEE   Y. 

THE  POSITION  AND  ARRANGEMENT  OF  COMETARY  ORBITS. 

THE  cosmical  masses  from  which  comets  are  de- 
rived seem  to  traverse  in  great  numbers  the  inter- 
stellar spaces.  In  consequence  of  the  sun's  pro- 
gressive motion,  these  nebulous  bodies  are  some- 
times drawn  toward  the  centre  of  our  system.  If, 
in  this  approach,  they  are  not  disturbed  by  any  of 
the  large  planets,  they  again  recede  in  parabolas  or 
hyperbolas.  When,  however,  as  must  sometimes 
be  the  case,  they  pass  near  Jupiter,  Saturn,  Uranus, 
or  Neptune,  their  orbits  may  be  transformed  into 
elongated  ellipses.  The  periodicity  of  many  comets 
may  thus  be  accounted  for. 

In  the  present  chapter  it  is  proposed  to  consider 
the  probable  consequences  of  the  sun's  motion 
through  regions  of  space  in  which  cometary  matter 
is  widely  diffused ;  to  compare  our  theoretical  de- 
ductions with  observed  phenomena;  and  thus  refer 
to  their  physical  cause  a  variety  of  facts  which  have 
hitherto  received  no  satisfactory  explanation.* 

1.  As  comets,  at  least  in  many  instances,  owe 
their  periodicity  to  the  disturbing  action  of  the 
major  planets,  and  as  this  planetary  influence  is 

*  This  chapter  is  the  substance  of  a  paper  read  before  the 
American  Philosophical  Society,  November  19,  1869. 

43 


44  COMETS   AND    METEORS. 

sometimes  sufficient,  especially  in  the  case  of  Ju- 
piter and  Saturn,  to  change  the  direction  of  cometary 
motion,  the  great  majority  of  periodic  comets  should 
move  in  the  same  direction  with  the  planets.  Now, 
of  the  comets  known  to  be  elliptical,  70  per  cent. 
have  direct  motion.  In  this  respect,  therefore,  theory 
and  observation  are  in  striking  harmony. 

2.  When  the  relative  positions  of  a  comet  and 
the  disturbing  planet  are  such  as  to  give  the  trans- 
formed orbit  of  the  former  a  small  perihelion  dis- 
tance, the  comet  must  return  to  the  point  at  which 
it  received  its  greatest  perturbation  ;  in  other  words, 
to  the  orbit  of  the  planet.  The  aphelia  of  the  comets 
of  short  period  ought  therefore  to  be  found,  for  the 
most  part,  in  the  vicinity  of  the  orbits  of  the  major  planets. 
This,  as  already  shown  in  Chapters  II.  and  III.,  is 
strikingly  the  case.  The  actual  distances  of  these 
aphelia,  however,  as  compared  with  the  respective 
distances  of  Jupiter,  Saturn,  Uranus  and  Neptune, 
are  presented  at  one  view  in  the  following  tables : 

I.     COMETS  WHOSE  APHELION  DISTANCES  ARE  NEARLY   EQUAL  TO 
5.20,  THE  RADIUS  OF  JUPITER'S  ORBIT. 

Comets.  Aph.  Dist. 

1.  Encke's 4.09 

2.  1819  IV 4.81 

3.  De  Vico's 5  02 

4.  Pigott's  (1783) 5.28 

5.  1867  II 5.29 

6.  1743  1 5.32 

7.  1766  II 5.47 

8.  1819  III 5.55 

9.  Brorsen's 5.64 

10.  D'Arrest's 5.75 

11.  Paye's 5.93 

12.  Biela's...  ..  6.19 


POSITION,  ETC.,  OF    COMETAKY   ORBITS.  45 

II.  COMETS  WHOSE  APHELION  DISTANCES  ARE  NEARLY  EQUAL 

TO  9.54,  THE  KADIUS  OF  SATURN'S  ORBIT. 

Comets.  Aph-.  Dist. 

1.  Peters'  (1846  VI.) 9.45 

2.  Tattle's  (1858  I.) 10.42 

III.  COMETS  WHOSE  APHELION  DISTANCES  ARE  NEARLY  EQUAL 

TO  19.18,  THE  KADIUS  OF  URANUS'S  ORBIT. 

Comets.  Aph.  Dist. 

1.  1867  1 19.28 

2.  November  meteors 19.65 

3.  1866  1 19.92 

IV.  COMETS  WHOSE  APHELION  DISTANCES  ARE  NEARLY  EQUAL 

TO  30.04,  THE  RADIUS  OF  NEPTUNE'S  ORBIT. 

Comets.  Aph.  Dist. 

1.  Westphal's  (1852  IV.) 31.97 

2.  Pons'  (1812) 33.41 

3.  Gibers'  (1815) 34.05 

4.  De  Vice's  (1846  IV.) 34.35 

5.  Brorsen's  (1847V.) 35.07 

6.  Halley's  * 35.37 

The  coincidences  here  pointed  out  (some  of  which 
have  been  noticed  by  others)  appear,  then,  to  be 
necessary  consequences  of  the  motion  of  the  solar 
system  through  spaces  occupied  by  meteoric  nebulae. 
Hence  the  observed  facts  receive  an  obvious  expla- 
nation. 

In  regard  to  comets  of  long  period  we  have  only 
to  remark  that,  for  anything  we  know  to  the  con- 
trary, there  may  be  causes  of  perturbation  far  ex- 
terior to  the  orbit  of  Neptune. 

3.  From  what  we  observe  in  regard  to  the  larger 
bodies  of  the  universe — a  clustering  tendency  being 

*  Halley's  comet  in  aphelio  is  too  remote  from  the  plane  of  the 
ecliptic  to  be  much  disturbed  by  Neptune.  Has  the  original 
position  of  the  orbit  been  changed  by  Jupiter's  influence? 


46  COMETS    AND    METEORS. 

everywhere  apparent, — it  seems  highly  improbable 
that  cometic  matter  should  be  uniformly  distributed 
in  the  sidereal  spaces.  We  would  expect,  on  the 
contrary,  to  find  it  collected  in  groups  or  clusters. 
This  view  is  also  in  remarkable  harmony  with  the 
facts  of  observation.  In  150  years,  from  1600  to 
1750,  16  comets  were  visible  to  the  naked  eye;  of 
which  8  appeared  in  the  25  years  from  1664  to  1689. 
Again,  during  60  years,  from  1750  to  1810,  only  5 
comets  were  visible  to  the  naked  eye,  while  in 
the  next  50  years  there  were  double  that  num- 
ber. The  probable  cause  of  such  variations  is  suf- 
ficiently obvious.  As  the  sun  in  its  progressive 
motion  approaches  a  cometary  group,  the  latter  is 
drawn  toward  the  centre  of  our  system ;  the  nearer 
members  with  greater  velocity  than  the  more  re- 
mote. Those  of  the  same  cluster  would  enter  the 
solar  domain  at  periods  not  very  distant  from  each 
other ;  the  forms  of  their  orbits  depending  upon 
their  original  relative  positions  with  reference  to 
the  sun's  course,  and  also  on  planetary  perturba- 
tions. It  is  evident  also  that  the  passage  of  the 
solar  system  through  a  region  of  space  compara- 
tively destitute  of  cometic  clusters  would  be  indi- 
cated by  a  corresponding  paucity  of  comets. 

4.  The  line  of  apsides  of  a  large  proportion  of 
comets  will  be  approximately  coincident  with  the 
solar  orbit.  The  point  towards  which  the  sun  is 
moving  is  in  longitude  about  260°.  The  quadrants 
bisected  by  this  point  and  that  directly  opposite 
extend  from  215°  to  305°,  and  from  35°  to  125°. 
The  number  of  cometary  perihelia  found  in  these 
quadrants  up  to  July,  1868  (periodic  comets  being 


POSITION,  ETC.,  OP    COMETARY    ORBITS.  47 

counted  but  once)  was  159,  or  62  per  cent.  ;  in  the 
other  two  quadrants,  98,  or  38  per  cent. 

This  tendency  of  the  perihelia  to  crowd  together 
in  two  opposite  regions  has  been  noticed  by  different 
writers. 

5.  Comets  whose  positions  before  entering  our 
system  were  very  remote  from  the  solar  orbit  must 
have  overtaken  the  sun  in  its  progressive  motion; 
hence  their  perihelia  must  fall,  for  the  most  part,  in' 
the  vicinity  of,the  point  towards  which  the  sun  is 
moving;  and  they  must  in  general  have  very  small 
perihelion  distances.  Now,  what  are  the  observed 
facts  in  regard  to  the  longitudes  of  the  perihelia  of 
the  comets  which  have  approached  within  the  least 
distance  of  the  sun's  surface?  But  three  have  had  a 
perihelion  distance  less  than  0.01.  All  these,  it  will 
be  seen  by  the  following  table,  have  their  perihelia 
in  close  proximity  to  the  point  referred  to: 

I.  COMETS  WHOSE  PERIHELION  DISTANCES   ARE  LESS  THAN  0.01. 

Perihelion  Passage.  Per.  Dist.  Long,  of  Per. 

1.  1668,  Feb  ................  28rf.'l3A.     0.0047     277°  2' 

2.  1680,  Dec  ................  17   23       00062     262  49 

3.  1843,  Feb  ................  27    9      0.0055     278  39 

In  Table  II.  all  but  the  last  have  their  perihelia  in 
the  same  quadrant. 

II.  COMETS  WHOSE  PERIHELION  DISTANCES  ARE  GREATER  THAN 

0.01  AND  LESS  THAN  0.05. 


Perihelion  Passage. 
1    1689   Nov                    29<2 

4h 

Per.  Dist. 
0  0189 

Long,  of  Per. 
269°    41' 

2    1816   March                  1 

8 

0  0485 

267     35 

3    1826   Nov                   18 

9 

00268 

315     31 

4    1847    March  .             30 

6 

0  0425 

276       2 

5.  1865,  Jan...              ...14 

7 

0.0260 

141     15 

The  perihelion  of  the  first  comet  in  Table  III.  is 


48  COMETS  AND   METEORS. 

remote  from  the  direction  of  the  sun's  motion;  that 
of  the  second  is  distant  but  14°,  and  ofvthe  third 
21°. 

III.   COMETS   WHOSE  PERIHELION  DISTANCES   ABE  GREATER 

THAN   0.05   AND    LESS    THAN   0.1. 

Perihelion  Passage.  Per.  Dist.  Long,  of  Per. 

1.  1593,  July ISd.   13A.  0.0891  176°    19' 

2.  1780,  Sept 30      22  0.0963  246     35 

3.  1821,  March 21      12  0.0918  239     29 

With  greater  perihelion  distances  the  tendency  of 
the  perihelia  to  crowd  together  round  the  point  indi- 
cated is  less  distinctly  marked. 

6.  Few  comets  of  small  perihelion  distance  should 
have  their  perihelia  in  the  vicinity  of  longitude  80°, 
the  point  opposite  that  towards  which  the  sun  is 
moving.  Accordingly  we  find,  by  examining  a 
table  of  cometary  elements,  that  with  a  perihelion 
distance  less  than  0.1  there  is  not  a  single  perihelion 
between  35°  and  125°;  between  0.1  and  0.2  but  3; 
and  between  0.2  and  0.3  only  1. 


CHAPTER   VI. 

THE    DISINTEGRATION    OF    COMETS. 

THE  fact  that  in  several  instances  meteoric  streams 
move  in  orbits  identical  with  those  of  certain  comets 
was  first  established  by  the  researches  of  Signor 
Schiaparelli.  The  theory,  however,  of  an  intimate 
relationship  between  comets  and  meteors  was  advo- 
cated by  the  writer  as  long  since  as  1861,*- — several 
years  previous  to  the  publication  of  Schiaparelli's 
memoirs.  In  the  essay  here  referred  to  it  was 
maintained — 

1.  That  meteors  and  meteoric  rings  uare  the  debris 
of  ancient  but  now  disintegrated  comets  whose  mat- 
ter has  become  distributed  around  their  orbits." 

2.  That  the  separation  of  Biela's  comet  as  it  ap- 
proached the  sun  in  December,  1845,  was  but  one 
in  a  series  of  similar  processes  which  would  proba- 
bly continue  until  the  individual  fragments  would 
become  invisible. 

3.  That  certain   luminous  meteors  have  entered 
the  solar  system  from  the  interstellar  spaces. f 

4  That  the  orbits  of  some  meteors  and  periodic 
comets  have  been  transformed  into  ellipses  by  plan- 
etary perturbation  ;  and 

*  Danville  Quarterly  Review,  December,  1861. 
f  Others,  it  was  supposed,  might  have  originated  within  the 
system, — a  view  which  the  writer  has  not  wholly  abandoned. 

5  49 


50  COMETS   AND    METEORS. 

5.  That  numerous  facts — some  observed  in  ancient 
and  some  in  modern  times — have  been  decidedly 
indicative  of  cometary  disintegration. 

What  was  thus  proposed  as  theory  has  been  since 
confirmed  as  undoubted  facts.  When  the  hypothe- 
sis was  originally  advanced,  the  data  required  for 
its  mathematical  demonstration  were  entirely  want- 
ing. The  evidence,  however,  by  which  it  was  sus- 
tained was  sufficient  to  give  it  a  high  degree  of 
probability. 

The  existence  of  a  divellent  force  by  which  comets 
near  their  perihelia  have  been  separated  into  parts 
is  clearly  shown  by  the  following  facts.  Whether 
this  force,  as  suggested  by  Schiaparelli,  is  simply  the 
unequal  attraction  of  the  sun  on  different  parts  of 
the  nebulous  mass,  or  whether,  in  accordance  with 
the  views  of  other  astronomers,  it  is  to  be  regarded 
as  a  cosrnical  force  of  repulsion,  is  a  question  left  for 
future  discussion. 

HISTORICAL  FACTS. 

1.  Seneca  informs  us  that  Ephoras,  a  Greek  writer 
of  the  fourth  century  before  Christ  had  recorded  the 
singular  fact  of  a  comet's  separation  into  two  distinct 
parts.*     This  statement  was  deemed  incredible  by 
the  Roman  philosopher,  inasmuch  as  the  occurrence 
was  then  without  a  parallel.      More  recent  observa- 
tions of  similar  phenomena  leave  no  room  to  ques- 
tion the  historian's  veracity. 

2.  The  head  of  the  great  comet  of  A.D.  389,  ac- 

*  "  Quaest.  Nut.,"  lib.  vii.,  cap.  xvi. 


HISTORICAL    FACTS.  51 

cording  to  the  writers  of  that  period,  was  "  composed 
of  several  small  stars."  (Hind's  "Comets,"  p.  103.) 

3.  On  Jane  27,  A.D.  416,  two  comets  appeared  in 
the  constellation  Hercules,  and  pursued  nearly  the 
same  apparent  path.     Probably  at  a  former  epoch 
the  pair  had  constituted  a  single  comet.* 

4.  On  August  4,  813,  "a  comet  was  seen  which 
resembled  two  moons  joined  together."     They  sub- 
sequently separated,  the  fragments  assuming  differ- 
ent forms,  f 

5.  The  Chinese  annals  record  the  appearance  of 
three  comets — one  large  and  two  smaller  ones — at 
the  same  time,  in  the  year  896  of  our  era.     "  They 
traveled  together  for  three  days.      The  little  ones 
disappeared  first,  and  then  the  large  one."J     The 
bodies  were  probably  fragments  of  a  large  comet 
which,  on  approaching  the  sun,  had  been  separated 
into  parts  a  short  time  previous  to  the  date  of  their 
discovery. 

6.  The  third  comet  of  1618. — The  great  comet  of 
1618  exhibited  decided  symptoms  of  disintegration. 
When  first  observed  (on  November  30),  its  appear- 
ance was  that  of  a  lucid  and  nearly  spherical  mass. 
On  the  eighth  day  the  process  of  division  was  dis- 
tinctly noticed,  and  on  the  20th  of  December  it 
resembled  a  cluster  of  small  stars. § 

7.  The  comet  0/1661. — The  elements  of  the  comets 
of  1532  and  1661  have  a  remarkable  resemblance, 

*  Chambers'  "  Descr.  Astr.,"  p.  374. 
f  Ibid.,  p.  383. 
%  Ibid.,  p.  388. 

g  Hevelius,  "Cometographia,"  p.  341.     See  also  Grant's  "Hist, 
of  Phys.  Astr.,"  p.  302. 


52  COMETS   AND   METEORS. 

and  previous  to  the  year  1790  astronomers  regarded 
the  bodies  as  identical.  The  similarity  of  the  ele- 
ments is  seen  at  a  glance  in  the  following  table: 

Comet  of  1532.  Comet  of  1661. 

Longitude  of  perihelion 111°     48'  115°      16' 

Longitude  of  ascending  node 87       23  81       54 

Inclination 32       36  33         I 

Perihelion  distance 0.5192  0.4427 

Motion Direct.  Direct. 

The  elements  of  the  former  are  by  Gibers;  those 
of  the  letter  by  Mechain.  The  return  of  the  comet 
about  1790,  though  generally  expected,  was  looked 
for  in  vain.  As  a  possible  explanation  of  this  fact, 
it  is  interesting  to  recur  to  an  almost  forgotten  state- 
ment of  Hevelius.  This  astronomer  observed  in  the 
comet  of  1661  an  apparent  breaking  up  of  the  body 
into  separate  fragments.*  The  case  may  be  analo- 
gous to  that  of  Biela's  comet. 

8.  The  identity  of  the  comets  of  1866  and  1366, 
first  suggested  by  Professor  H.  A.  Newton,  is  now 
unquestioned.  The  existence  then  of  a  meteoric 
swarm,  moving  in  the  same  track,  is  not  the  only 
evidence  of  the  original  comet's  partial  dissolution. 
The  comet  of  1866  was  invisible  to  the  naked  eye ; 
that  of  1366,  seen  under  nearly  similar  circum- 
stances, was  a  conspicuous  object.  The  statement 
of  the  Chinese  historian  that  "  it  appeared  nearly  as 
large  as  a  tow  measure, "f  though  somewhat  indefi- 
nite, certainly  justifies  the  conclusion  that  its  magni- 
tude has  greatly  diminished  during  the  last  500 
years.  The  meteors  moving  in  the  same  orbit  are 
doubtless  the  products  of  this  gradual  separation. 

*  "Cometographia,"  p.  417. 
f  Williams'  "  Chinese  Observations  of  Comets,"  p.  73. 


HISTORICAL   FACTS.  53 

9.  The  bipartition  of  Biela's  comet  in  1845,  as 
well  as  the  non-appearance  of  the  two  fragments  in 
1865  and  1872,*  were  referred  to  in  a  previous 
chapter. 

The  comet  of  Halley,  if  we  may  credit  the  descrip- 
tions given  by  ancient  writers,  has  been  decreasing 
in  brilliancy  from  age  to  age.  The  same  is  true  in 
regard  to  several  others  believed  to  be  periodic.  The 
comet  of  A.D.  1097  had  a  tail  50°  long!  At  its  return, 
in  March,  1840,  the  length  of  its  tail  was  only  5°. 
The  third  comet  of  1790  and  the  first  of  1825  are 
supposed,  from  the  similarity  of  their  elements, 
to  be  identical.  Each  perihelion  passage  occurred 
in  May,  yet  the  tail  at  the  former  appearance  wa'k 
4°  in  length,  at  the  latter  but  2J°.  Other  instances 
might  be  specified  of  this  apparent  gradual  disso- 
lution. It  would  seem,  indeed,  extremely  improb- 
able that  the  particles  driven  off  from  comets  in 
their  approach  to  the  sun,  forming  tails  extending 
millions  of  miles  from  the  principal  mass,  should 
«again  be  collected  around  the  same  nuclei. 

The  fact,  then,  that  meteors  move  in  the  same 
orbits  with  comets  is  but  a  consequence  of  that  dis- 
ruptive process  so  clearly  indicated  by  the  phe- 
nomena described.  In  this  view  of  the  subject, 
comets — even  such  as  move  in  elliptic  orbits — are 
not  to  be  regarded  as  permanent  members  of  the 
solar  system.  Their  debris  becomes  gradually  scat- 
tered around  the  orbit.  Some  parts  of  the  nebulous 
ring  will  be  more  disturbed  than  others  by  planet- 


*  One  of  the  parts  was  seen  at  Madras,  India,  on  the  mornings 
of  December  2  and  3,  1872. 

5* 


54  COMETS   AND    METEOKS. 

ary  perturbation.  Portions  of  such  streams  as 
nearly  intersect  the  earth's  path  sometimes  pene- 
trate the  atmosphere.  Their  rapid  motion  renders 
them  luminous.  If  very  minute,  they  are  burnt  up 
or  dissipated  without  leaving  any  solid  deposit;  we 
then  have  the  phenomena  of  shooting-stars.  "When, 
however,  as  is  sometimes  the  case,  they  contain  a 
considerable  quantity  of  solid  matter,  they  reach 
the  earth's  surface  as  meteoric  stones. 


II. 


METEORS 


CHAPTER    VII. 

METEORIC     STONES. 

ALTHOUGH  numerous  instances  of  the  fall  of  aero- 
lites had  been  recorded,  some  of  them  apparently 
well  authenticated,  the  occurrence  long  appeared 
too  marvelous  and  improbable  to  gain  credence 
with  scientific  men.  Such  a  shower  of  rocky  frag- 
ments occurred,  however,  on  the  26th  of  April, 
1803,  at  L'Aigle,  in  France,  as  forever  to  dissipate 
all  doubt  on  the  subject.  Similar  displays  since 
that  time  have  been  frequently  witnessed; — indeed 
scarcely  a  year  passes  without  the  fall  of  meteoric 
stones  in  some  part  of  the  earth,  either  singly  or  in 
clusters.  It  would  not  comport  with  the  design  of 
the  present  treatise  to  give  an  extended  list  of  these 
phenomena.  The  following  account,  however,  in- 
cludes the  most  important  instances  in  which  the 
fall  of  meteoric  stones  has  been  actually  observed  : 

(1.)  1478  B.C. — According  to  the  celebrated  Pa- 
rian chronicle,  an  aerolite,  or  thunder-stone,  as  it 
was  called,  fell  in  the  island  of  Crete,  about  1478 
years  before  the  Christian  era.  This  is  undoubt- 
edly the  most  ancient  stone-fall  on  record.  Mete- 
oric masses  have  been  found,  however,  the  fall  of 
which  probably  occurred  at  an  epoch  still  more 
ancient. 

(2.)  1200  B.C. — A  number  of  stones,  which  were 

5T 


58  COMETS   AND   METEORS. 

anciently  preserved  in  Orchomenos,  a  town  of 
Boeotia,  were  said  to  have  fallen  from  heaven  about 
twelve  centuries  before  our  era. 

(3.)  1168  B.C. — A  mass  of  iron,  as  we  learn  from 
the  Parian  chronicle,  was  seen  to  descend  upon 
Mount  Ida,  in  Crete. 

(4.)  654  B.C.— According  to  Livy,  a  number  of 
meteoric  stones  fell  on  the  Albau  Hill,  near  Rome, 
about  the  year  654  B.C. 

(5.)  616  B.C.,  January  14. — It  is  related  in  the 
Chinese  annals  that  on  the  14th  of  January,  616 
B.C.,  a  meteoric  stone-fall  broke  several  chariots  and 
killed  ten  men. 

(6.)  466  B.C. — A  mass  of  rock,  described  as  "  of 
the  size  of  two  millstones,"  fell  at  ^Egospotamos, 
in  Thrace.  An  attempt  to  rediscover  this  meteoric 
mass,  so  celebrated  in  antiquity,  was  recently  made, 
but  without  success.  Notwithstanding  this  failure, 
Humboldt  expressed  the  hope  that,  as  such  a  body 
would  be  difficult  to  destroy,  it  may  yet  be  found, 
"  since  the  region  in  which  it  fell  is  now  become  so 
easy  of  access  to  European  travelers." 

(7.)  465  B.C.— The  famous  stone  called  the  "  Mo- 
ther of  the  Gods,"  and  which  is  described  or  alluded 
to  by  many  ancient  writers,  was  said  to  have  fallen 
from  the  skies.  The  poet  Pindar  was  seated  on  a 
hill  at  the  time  of  its  descent,  and  the  meteorite 
struck  the  earth  near  his  feet.  The  stone,  as  it  fell, 
was  encircled  by  fire.  "It  is  said  to  have  been  of 
moderate  dimensions,  of  a  black  hue,  of  an  irregu- 
lar, angular  shape,  and  of  a  metallic  aspect.  An 
oracle  had  predicted  that  the  Romans  would  con- 
tinue to  increase  in  prosperity  if  they  were  put 


METEORIC    STONES.  59 

in  possession  of  this  precious  deposit ;  and  Publius 
Scipio  Nasico  was  accordingly  deputed  to  Attalus, 
King  of  Pergamus,  to  obtain  and  receive  the  sacred 
idol,  whose  worship  was  instituted  at  Rome  204 
years  before  the  Christian  era." — Edinburgh  Ency- 
clopedia. 

(8.)  A.D.  921. — An  immense  aerolite  fell  into  the 
river  (a  branch  of  the  Tiber)  at  Kami,  in  Italy.  It 
projected  three  or  four  feet  above  the  surface  of  the 
water. 

(9.)  1492,  November  1. — An  aerolite,  weighing 
276  pounds,  fell  at  Ensisheirn,  in  Alsace,  penetra- 
ting the  earth  to  the  depth  of  three  feet.  This 
stone,  or  the  greater  part  of  it,  may  still  be  seen  at 
Ensisheim. 

(10.)  1511,  September  14. — At  noon  an  almost 
total  darkening  of  the  heavens  occurred  at  Crema. 
/'During  this  midnight  gloom,"  says  a  writer  of 
that  period,  "  unheard-of  thunders,  mingled  with 
awful  lightnings,  resounded  through  the  heavens. 
.  On  the  plain  of  Crerna,  where  never  before 
was  seen  a  stone  the  size  of  an  egg,  there  fell 
pieces  of  rock  of  enormous  dimensions  and  of  im- 
mense weight.  It  is  said  that  ten  of  these  were 
found,  weighing  100  pounds  each."  A  monk  was 
struck  dead  at  Crema  by  one  of  these  rocky  frag- 
ments. This  terrific  display  is  said  to  have  lasted 
two  hours,  and  1200  aerolites  were  subsequently 
found. 

(11.)  1637,  November  29.— A  stone,  weighing  54 
pounds,  fell  on  Mount  Vaison,  in  Provence. 

(12.)  1650,  March  30. — A  Franciscan  monk  was 
killed  at  Milan  by  the  fall  of  a  meteoric  stone. 


60  COMETS    AND    METEORS. 

(13.)  1674. — Two  Swedish  sailors  were  killed  on 
shipboard  by  the  fall  of  an  aerolite. 

(14.)  1751,  May  26. — Two  meteoric  masses,  con- 
sisting almost  wholly  of  iron,  fell  near  Agram,  the 
capital  of  Croatia.  The  larger  fragment,  which 
weighs  72  pounds,  is  now  in  Vienna. 

(15.)  1790,  July  24.— Between  9  and  10  o'clock 
at  night  a  very  large  meteor  was  seen  near  Bor- 
deaux, France.  Over  Barbotan  a  loud  explosion 
was  heard,  which  was  followed  by  a  shower  of  me- 
teoric stones  of  various  magnitudes. 

(16.)  1794,  July. — A  fall  of  about  a  dozen  aero- 
lites occurred  at  Sienna,  Tuscany. 

(17.)  1795,  December  13. — A  large  meteoric 
stone  fell  near  Wold  Cottage,  in  Yorkshire,  Eng- 
land. "  Several  persons  heard  the  report  of  an  ex- 
plosion in  the  air,  followed  by  a  hissing  sound ;  and 
afterward  felt  a  shock,  as  if  a  heavy  body  had  fallen, 
to  the  ground  at  a  little  distance  from  them.  One 
of  these,  a  plowman,  saw  a  huge  stone  falling  to- 
ward the  earth,  eight  or  nine  yards  from  the  place 
where  he  stood.  It  threw  up  the  mould  on  every 
side  ;  and  after  penetrating  through  the  soil,  lodged 
some  inches  deep  in  solid  chalk-rock.  Upon  being 
raised,  the  stone  was  found  to  weigh  56  pounds.  It 
fell  in  the  afternoon  of  a  mild,  but  hazy  day,  during 
which  there  was  no  thunder  or  lightning;  and  the 
noise  of  the  explosion  was  heard  through  a  consid- 
erable district." — Milners  Gallery  of  Nature,  p.  134. 

(18.)  1796,  February  19.— A  stone  of  10  pounds' 
weight  fell  in  Portugal. 

(19.)  1803,  April  26. — This  remarkable  shower 
was  referred  to  on  a  previous  page.  At  1  o'clock 


METEORIC   STONES.  61 

P.M.,  the  heavens  being  almost  cloudless,  a  tremen- 
dous noise,  like  that  of  thunder,  was  heard,  and  at 
the  same  time  an  immense  fire-ball  was  seen  mov- 
ing with  great  rapidity  through  the  atmosphere. 
This  was  followed  by  a  violent  explosion,  which 
lasted  several  minutes,  and  which  was  heard  not 
only  at  L'Aigle,  but  in  every  direction  around  it  to 
the  distance  of  70  miles.  Immediately  after,  a  great 
number  of  meteoric  stones  fell  to  the  earth,  gene- 
rally penetrating  to  some  distance  beneath  the  sur- 
face. Nearly  3000  of  these  fragments  were  found 
and  collected,  the  largest  weighing  about  17  pounds. 
The  occurrence  very  naturally  excited  great  atten- 
tion. M.  Biot,  under  the  authority  of  the  govern- 
ment, repaired  to  the  place,  collected  the  various 
facts  in  regard  to  the  phenomenon,  took  the  testi- 
mony of  witnesses,  etc.,  and  finally  embraced  the 
results  of  his  investigations  in  an  elaborate  memoir. 
(20.)  1807,  December  14. — A  large  meteor  ex- 
ploded over  Weston,  Connecticut.  The  height,  di- 
rection, velocity  and  magnitude  of  this  body  were 
discussed  by  Dr.  Bowditch  in  a  memoir  commu- 
nicated to  the  American  Academy  of  Arts  and 
Sciences  in  1815.  The  appearance  of  the  meteor 
occurred  about  6h.  15m.  A.M., — -just  after  daybreak. 
Its  apparent  diameter  was  half  that  of  the  full 
moon;  its  time  of  flight,  about  30  seconds.  Within 
less  than  a  minute  from  the  time  of  its  disappear- 
ance three  distinct  reports,  like  those  of  artillery, 
were  heard  over  an  area  several  miles  in  diameter. 
Each  explosion  was  followed  by  the  fall  of  meteoric 
stones.  Unlike  most  aerolites,  these  bodies  when 
first  found  were  so  soft  as  to  be  easily  pulverized 


62  COMETS    AND    METEORS. 

between  the  fingers.  On  exposure  to  the  air,  how- 
ever, they  gradually  hardened.  The  weight  of  the 
largest  fragment  was  35  pounds. 

(21.)  1859,  November  15.— Between  9  and  10 
o'clock  in  the  morning  an  extraordinary  meteor 
was  seen  in  several  of  the  New  England  States, 
New  York,  New  Jersey,  the  District  of  Columbia, 
and  Virginia.  The  apparent  diameter  of  the  head 
was  nearly  equal  to  that  of  the  sun,  and  it  had  a 
train,  notwithstanding  the  bright  sunshine,  several 
degrees  in  length.  Its  disappearance  on  the  coast 
of  the  Atlantic  was  followed  by  a  series  of  the  most 
terrific  explosions.  It  is  believed  to  have  descended 
into  the  water,  probably  into  Delaware  Bay.  A 
highly  interesting  account  of  this  meteor,  by  Pro- 
fessor Loomis,  may  be  found  in  the  American  Jour- 
nal of  Science  and  Arts  for  January,  1860. 

(22.)  1860,  May  1.— About  20  minutes  before  1 
o'clock,  P.M.,  a  shower  of  meteoric  stones  fell  in  the 
southwest  corner  of  Guernsey  county,  Ohio.  Full 
accounts  of  the  phenomena  are  given  in  Silliman's 
Journal  for  July,  1860,  and  January  and  July,  1861, 
by  Professors  E.  B.  Andrews,  E.  W.  Evans,  J.  L. 
Smith,  and  D.  W.  Johnson.  From  these  interesting 
papers  we  learn  that  the  course  of  the  meteor  was 
about  40°  west  of  north.  Its  visible  track  was  over 
Washington  and  Noble  counties,  and  the  prolonga- 
tion of  its  projection,  on  the  earth's  surface,  passes 
directly  through  New  Concord,  in  the  southeast 
corner  of  Muskingum  county.  The  meteor  when 
first  seen  was  about  40  miles  from  the  earth's  sur- 
face. The  sky,  at  the  time,  was  for  the  most  part 
covered  with  clouds  over  northwestern  Ohio,  so 


METEORIC    STONES.  63 

that  if  any  portion  of  the  meteoric  mass  continued 
on  its  course  it  was  invisible.  The  velocity  of  the 
meteor,  in  relation  to  the  earth's  surface,  was  from 
three  to  four  miles  per  second ;  and  hence  its  abso- 
lute velocity  in  the  solar  system  must  have  been 
somewhat  greater  than  that  of  the  earth. 

"At  New  Concord,*  Muskingum  county,  where 
the  meteoric  stones  fell,  and  in  the  immediate 
neighborhood,  there  were  many  distinct  and  loud 
reports  heard.  At  New  Concord  there  was  first 
heard  in  the  sky,  a  little  southeast  of  the  zenith,  a 
loud  detonation,  which  was  compared  to  that  of  a 
cannon  fired  at  the  distance  of  half  a  mile.  After 
an  interval  of  ten  secondsy  another  similar  report. 
After  two  or  three  seconds  another,  and  so  on  with 
diminishing  intervals.  Twenty-three  distinct  'de- 
tonations were  heard,  after  which  the  sounds  be- 
came blended  together  and  were  compared  to  the 
rattling  fire  of  an  awkward  squad  of  soldiers,  and 
by  others  to  the  roar  of  a  railway  train.  These 
sounds,  with  their  reverberations,  are  thought  to 
have  continued  for  two  minutes.  The  last  sounds 
seemed  to  come  from  a  point  in  the  southeast  45° 
below  the  zenith.  The  result  of  this  cannonading  was 
the  falling  of  a  large  number  of  stony  meteorites  upon 
an  area  of  about  10  miles  long  by  3  wide.  The  sky 
was  cloudy,  but  some  of  the  stones  were  seen  first 
as  '  black  specks',  then  as  '  black  birds',  and  finally 
falling  to  the  ground.  A  few  were  picked  up  within 
20  or  30  minutes.  The  warmest  was  no  warmer 


*  New  Concord  is  close  to  the  Guernsey  county  line.     Nearly 
all  the  stones  fell  in  Guernsey. 


64  COMETS   AND   METEORS. 

than  if  it  had  lain  on  the  ground  exposed  to  the 
sun's  rays.  They  penetrated  the  earth  from  two  to 
three  feet.  The  largest  stone,  which  weighed  103 
pounds,  struck  the  earth  at  the  foot  of  a  large  oak- 
tree,  and,  after  cutting  off  two  roots,  one  five  inches 
in  diameter,  and  grazing  a  third  root,  it  descended 
two  feet  ten  inches  into  hard  clay.  This  stone  was 
found  resting  under  a  root  that  was  not  cut  off. 
This  would  seemingly  imply  that  it  entered  the 
earth  obliquely." 

Over  thirty  of  the  stones  which  fell  were  discov- 
ered, while  doubtless  many,  especially  of  the  smaller, 
being  deeply  buried  beneath  the  soil,  entirely  es- 
caped observation.  The  weight  of  the  largest  ten 
was  418  pounds. 

(23.)  1860,  July  14.— About  2  o'clock  P.M.  on 
the  14th  of  July,  1860,  a  shower  of  aerolites  fell  at 
Dhurmsala,  in  India.  The  fall  was  attended  by  a 
tremendous  detonation,  which  greatly  terrified  the 
inhabitants  of  the  district.  The  natives,  supposing 
the  stones  to  have  been  thrown  by  some  of  their 
deities  from  the  summit  of  the  Himalayas,  carried 
off  many  fragments  to  be  kept  as  objects  of  religious 
veneration.  Lord  Canning  and  Mr.  J.  R.  Saunders 
succeeded,  however,  in  obtaining  numerous  speci- 
mens, which  they  forwarded  to  the  British  Museum 
and  several  European  cabinets.  They  are  earthy 
aerolites,  of  a  specific  gravity  somewhat  greater 
than  that  of  granite. 

(24.)  1864,  May  14. — Early  in  the  evening  a  very 
large  and  brilliant  meteor  was  seen  in  France, 
from  Paris  to  the  Spanish  border.  At  Montauban 
and  in  the  vicinity  loud  explosions  were  heard, 


METEORIC    STONES.  65 

which  were  followed  by  showers  of  meteoric  stones 
near  the  villages  of  Orgueil  and  Nohic.  The  prin- 
cipal facts  in  regard  to  the  meteor  are  the  following: 

Elevation  when  first  seen,  over 55  miles 

"          at  the  time  of  its  explosion 20     " 

Inclination  of  its  path  to  the  horizon 20°  or  25° 

Velocity  per  second,  about 20  miles, 

or  equal  to  that  of  the  earth's  orbital  motion. 

"This  example,"  says  Professor  Newton,  "affords 
the  strongest  proof  that  the  detonating  and  stone- 
producing  meteors  are  phenomena  not  essentially 
unlike." 

(^5.)  1868,  January  30. — It  is  obviously  a  mat- 
ter of  much  importance  that  the  composition  and 
general  characteristics  of  aerolites,  together  with 
the  phenomena  attending  their  fall,  should  be  care- 
fully noted;  as  such  facts  have  a  direct  bearing  on 
the  theory  of  their  origin.  In  this  regard  the  me- 
moirs of  Professors  J.  Gr.  Galle,  of  Breslau,  and  Gr. 
vom  Rath,  of  Bonn,  on  a  meteoric  fall  which  oc- 
curred at  Pultusk,  Poland,  on  the  30th  of  January, 
1868,  have  more  than  ordinary  interest.  These  me- 
moirs establish  the  fact  that  the  aerolites  of  the 
Pultusk  shower  entered  our  atmosphere  as  a  swarm  or 
cluster  of  distinct  meteoric  masses.  It  is  shown, 
moreover,  by  Dr.  Galle  that  this  meteor-group  had 
a  proper  motion  when  it  entered  the  solar  system  of 
at  least  from  4J  to  7  miles  per  second. 

The  foregoing  list  contains  but  a  small  proportion 
of  the  meteoric  stones  whose  fall  has  been  actually 
observed.  But,  besides  these,  other  masses  have 
been  found  so  closely  similar  in  structure  to  aero- 
lites whose  descent  has  been  witnessed,  as  to  leave 

6* 


66  COMETS   AND    METEORS. 

no  doubt  in  regard  to  their  origin.  One  of  these  is 
a  mass  of  iron  and  nickel,  weighing  1680  pounds, 
found  by  the  traveler  Pallas,  in  1749,  at  Abakansk, 
in  Siberia.  This  immense  aerolite  may  be  seen  in 
the  Imperial  Museum  at  St.  Petersburg.  On  the 
plain  of  Otumpa,  in  Buenos  Ayres,  is  a  meteoric 
mass  7J  feet  in  length,  partly  buried  in  the  ground. 
Its  estimated  weight  is  about  16  tons.  A  specimen 
of  this  stone,  weighing  1400  pounds,  has  been  re- 
moved and  deposited  in  one  of  the  rooms  of  the 
British  Museum.  A  similar  block,  of  meteoric 
origin,  weighing  more  than  six  tons,  was  discov- 
ered some  years  since  in  the  province  of  Bahia,  in 
Brazil. 

GENERAL  REMARKS. 

1.  A  Committee  on  Luminous  Meteors  was  ap- 
pointed several  years  since  by  the  British  Associa- 
tion for  the  Advancement  of  Science.  This  com- 
mittee, consisting  at  present  of  James  Glaisher, 
F.R.S.,  Robert  P.  Greg,  F.R.S.,  Alexander  S.  Her- 
schel,  F.E.A.S.,  and  Charles  Brooke,  F.R.S.,  report 
from  year  to  year  not  only  their  own  observations 
on  aerolites,  fire-balls,  and  falling  stars,  but  also  such 
facts  bearing  upon  the  subject  as  can  be  derived 
from  other  sources.  An  analysis  of  these  reports 
justifies  the  conclusion  that  meteoric  stone-falls,  like 
star-showers,  occur  with  greater  frequency  than 
usual  on  or  about  particular  days.  These  epochs, 
established  with  more  or  less  certainty,  are  the  fol- 
lowing : 


METEORIC    STONES. 


67 


(••) 

(6.) 
(c.) 


January 


)    February 


(/.)  March 

(9-)  il 

(A.)  April 

(i.) 

(J.)  May 

(*•)  " 

(Z.)  " 
(wi.)  June 


4th. 
16th. 
29th. 
10th. 

15th— 18th. 

6th. 

12th. 

1st. 

10th— 14th. 

8th— 9th. 

13th— 14th. 

17th— 19th. 

3d. 

9th. 


(o.)   June 
(p.)     « 
(q.)   July 
(r.)      » 
(s.)   August 


12th. 

16th. 

3d— 4th. 

14th— 17th. 

5th— 7th. 

llth. 

4th— 10th. 
13th. 
5th. 

12th— 13th. 
27th— 30th. 
5th. 

8th— 14th. 
27th. 


(w.)  September 
(17.)  October 
(w>.)  November 

(*)         " 

(2/0         " 

(z.)   December 

(*'.)         « 

(*".)       « 

2.  It  is  worthy  of  remark  that  no  new  elements 
have  been  found  in  meteoric  stones.     Humboldt,  in 
his    "  Cosmos,"  called  attention  to  this  interesting 
fact.    "  I  would  ask,"  he  remarks,  "  why  the  elemen- 
tary substances  that  compose  one  group  of  cosmical 
bodies,  or  one  planetary  system,  may  not  in  a  great 
measure  be  identical?     Why  should  we  not  adopt 
this  view,  since  we  may  conjecture  that  those  plan- 
etary bodies,  like  all  the  larger  or  smaller  agglom- 
erated masses  revolving  round  the  sun,  have  been 
thrown  off  from  the  once  far  more  expanded  solar 
atmosphere,  and  have  been  formed  from  vaporous 
rings  describing  their  orbits  round  the  central  body?" 

3.  But  while  aerolites  contain  no  elements  but 
such  as  are  found  in  the  earth's  crust,  the  manner 
in  which  these  elements  are  combined  and  arranged 
is  so  peculiar  that  a  skillful  mineralogist  will  readily 
distinguish  them  from  terrestrial  substances. 

4.  Of  the  eighteen  or  nineteen  elements  hitherto 
observed  in  meteoric   stones,  iron  is  found  in  the 
greatest  abundance.   The  specific  gravities  vary  from 
1.94  to  7.90J. :  the  former  being  that  of  the  stone  of 


68  COMETS   AND    METEORS. 

Alais;  the  latter  that  of  the  meteorite  of  Wayne 
county,  Ohio,  described  by  Professor  J.  L.  Smith  in 
SUliman's  Journal  for  November,  1864,  p.  385. 

5.  The  average  number  of  aerolitic  falls  in  a  year 
was  estimated  by  Schreibers  at  700.    Baron  Reichen- 
bach,  however,  after  a  discussion  of  the  data  at  hand, 
makes  the  number  much  larger.     He  regards  the 
probable  annual  average  for  the  entire  surface  of  the 
earth  as  not  less  than  4500.    This  would  give  twelve 
daily  falls.     They  are  of  every  variety  as  to.  magni- 
tude, from  a  weight  of  less  than  a  single  ounce  to  over 
fifteen  tons.     The  baron  even  suspects  the  meteoric 
origin  of  large  masses  of  dolerite  which  all  former 
geologists  had  considered  native  to  our  planet. 

6.  An  analysis  of  any  extensive  table  of  meteor- 
ites and  fire-balls  proves  that  a  greater  number  of 
aerolitic  falls  have  been  observed  during  the  months 
of  June  and  July,  when  the  earth  is  near  its  aphe- 
lion, than  in  December  and  January,  when  near  its 
perihelion.     It  is  found,  however,  that  the  reverse 
is  true  in  regard  to  bolides,  or  fire-balls.     These 
facts  are  susceptible  of  an  obvious  explanation.    The 
fall  of  meteoric  stones  would  be  more  likely  to  escape 
observation  by  night  than  by  day,  on  account  of  the 
relatively  small  number  of  observers.     But  the  days 
are  shortest  when  the  earth  is  in  perihelion,  and 
longest  when  in  aphelion;  the  ratio  of  their  lengths 
being  nearly  equal  to  that  of  the  corresponding  num- 
bers of  aerolitic  falls.   On  the  other  hand,  it  is  obvious 
that  fire-balls,  unless  very  large,  would  not  be  visible 
during  the  day.    The  observed  number  will  therefore 
be  greatest  when  the  nights  are  longest;   that  is, 
when  the  earth  is  near  its  perihelion.    This,  it  will  be 
found,  is  precisely  in  accordance  with  observation. 


CHAPTEE    VIII. 

.        SHOOTING-STARS. — METEORS    OF   NOVEMBER   14. 

ALTHOUGH  shooting-stars  have  doubtless  been  ob- 
served in  all  ages  of  the  world,  it  is  only  within  the 
last  half  century  that  they  have  attracted  the  special 
attention  of  scientific  men.  A  few  efforts  had  been 
made  to  determine  the  height  of  such  meteors,  but 
the  first  general  interest  in  the  subject  was  excited 
by  the  brilliant  meteoric  display  of  November  13, 
1833.  This  shower  of  fire  can  never  be  forgotten 
by  those  who  witnessed  it.  The  meteors  were  ob- 
served from  the  West  Indies  to  British  America, 
and  from  60°  to  100°  west  longitude  from  Green- 
wich. As  early  as  10  o'clock  on  the  evening  of  the 
12th  shooting-stars  were  observed  with  unusual  fre- 
quency; their  motions  being  generally  westward. 
Soon  after  midnight  their  numbers  became  so  ex- 
traordinary as  to  attract  the  attention  of  all  who 
happened  to  be  in  the  open  air.  The  meteors,  how- 
ever, became  more  and  more  numerous  till  4,  or 
half  past  4,  o'clock ;  and  the  fall  did  not  entirely 
cease  till  ten  minutes  before  sunrise.  From  2  to  6 
o'clock  the  numbers  were  so  great  as  to  defy  all 
efforts  at  counting  them  ;  while  their  brilliancy  was 
such  that  persons  sleeping  in  rooms  with  uncur- 
tained windows  were  aroused  by  their  light.  The 

69 


70  COMETS   AND    METEORS. 

meteors  varied  in  apparent  magnitude  from  the 
smallest  visible  points  to  fire-balls  equaling  the  moon 
in  diameter.  Occasionally  one  of  the  larger  class 
would  separate  into  several  parts,  and  in  some  in- 
stances a  luminous  train  remained  visible  for  three  or 
four  minutes.  ~No  sound  whatever  accompanied  the 
display.  It  was  noticed  by  many  observers  that  all 
the  meteors  diverged  from  a  point  near  the  star 
Gamma  Leonis  ;  in  other  words,  their  paths  if  traced 
backward  would  intersect  each  other  at  a  particular 
locality  in  the  constellation  Leo.  In  some  parts  of 
the  country  the  inhabitants  were  completely  terror- 
stricken  by  the  magnificence  of  the  display.  In  the 
afternoon  of  the  day  on  which  the  shower  occurred 
the  writer  met  with  an  illiterate  farmer  who,  after 
describing  the  phenomena  as  witnessed  by  himself, 
remarked  that  "  the  stars  continued  to  fall  till  none 
were  left,"  and  added,  "  I  am  anxious  to  see  how 
the  heavens  will  appear  this  evening;  I  believe  we 
shall  see  no  more  stars."  A  gentleman  of  South 
Carolina  described  the  effect  on  the  negroes  of  his 
plantation  as  follows: — "  I  was  suddenly  awakened 
by  the  most  distressing  cries  that  ever  fell  on  my 
ears.  Shrieks  of  horror  and  cries  for  mercy  I  could 
hear  from  most  of  the  negroes  of  the  three  planta- 
tions, amounting  in  all  to  about  600  or  800.  While 
earnestly  listening  for  the  cause  I  heard  a  faint 
voice  near  the  door,  calling  my  name.  I  arose,  and, 
taking  my  sword,  stood  at  the  door.  At  this  mo- 
ment I  heard  the  same  voice  still  beseeching  me  to 
arise,  and  saying,  l  0  my  Grod,  the  world  is  on  fire !' 
I  then  opened  the  door,  and  it  is  difficult  to  say 
which  excited  me  the  most, — the  awfulness  of  the 


SHOOTING-STARS.  71 

scene,  or  the  distressed  cries  of  the  negroes.  Up- 
wards of  a  hundred  lay  prostrate  on  the  ground, — 
some  speechless,  and  some  with  the  bitterest  cries, 
but  with  their  hands  raised,  imploring  God  to  save 
the  world  and  them.  The  scene  was  truly  awful ;  for 
never  did  rain  fall  much  thicker  than  the  meteors 
fell  towards  the  earth  ;  east,  west,  north,  and  south, 
it  was  the  same." 

At  the  time  of  this  wonderful  meteoric  display 
Captain  Hammond,  of  the  ship  Restitution,  had  just 
arrived  at  Salem,  Massachusetts,  where  he  observed 
the  phenomenon  from  midnight  till  daylight.  He 
recollected  with  astonishment  that  precisely  one 
year  before,  viz.,  on  the  13th  of  November,  1832,  he 
had  observed  a  similar  appearance  (although  the 
meteors  were  less  numerous)  at  Mocha,  in  Arabia. 
It  was  found,  moreover,  as  a  further  and  most  re- 
markable coincidence,  that  an  extraordinary  fall  of 
meteors  had  been  witnessed  on  the  12th  of  Novem- 
ber, 1799.  This  was  seen  and  described  by  Andrew 
Ellicott,  Esq.,  who  was  then  at  sea  near  Cape 
Florida.  It  was  also  observed  by  Humboldt  and 
Boupland,  in  Cumana,  South  America.  Baron 
Humboldt's  description  of  the  shower  is  as  follows : — 
"From  half  after  two,  the  most  extraordinary  lumin- 
ous meteors  were  seen  toward  the  east.  Thousands 
of  bolides  and  falling  stars  succeeded  each  other 
during  four  hours.  They  filled  a  space  in  the  sky 
extending  from  the  true  east  30°  toward  the  north 
and  south.  In  an  amplitude  of  60°  the  meteors 
were  seen  to  rise  above  the  horizon  at  E.N.E.  and 
at  E.,  describe  arcs  more  or  less  extended,  and  fall 
toward  the  south,  after  having  followed  the  direc- 


72  COMETS    AND    METEORS. 

tion  of  the  meridian.  Some  of  them  attained  a 
height  of  40°,  and  all  exceeded  25°  or  30°.  Mr. 
Bonpland  relates,  that  from  the  beginning  of  the 
phenomenon  there  was  not  a  space  in  the  firmament 
equal  in  extent  to  three  diameters  of  the  moon,  that 
was  not  filled  at  every  instant  with  bolides  and  fall- 
ing stars.  The  Guaiqueries  in  the  Indian  suburb 
came  out  and  asserted  that  the  firework  had  begun 
at  one  o'clock.  The  phenomenon  ceased  by  degrees 
after  four  o'clock,  and  the  bolides  and  falling  stars 
became  less  frequent;  but  we  still  distinguished 
some  toward  the  northeast  a  quarter  of  an  hour 
after  sunrise." 

This  wonderful  correspondence  of  dates  excited 
a  very  lively  interest  throughout  the  scientific  world. 
It  was  inferred  that  a  recurrence  of  the  phenomenon 
might  be  expected,  and  accordingly  arrangements 
were  made  for  systematic  observations  on  the  12th, 
13th,  and  14th  of  November.  The  periodicity  of 
the  shower  was  thus,  in  a  very  short  time,  placed 
wholly  beyond  question.  The  facts  in  regard  to 
the  phenomena  of  November  13,  1833,  were  col- 
lected and  discussed  by  Ol mated,  Twining,  and 
other  astronomers.  The  inquiry,  however,  very 
naturally  arose  whether  any  trace  of  the  same  me- 
teoric group  could  be  found  in  ancient  times.  To 
determine  this  question  many  old  historical  records 
were  ransacked  by  the  indefatigable  scientist,  Ed- 
ward C.  Herrick,  in  our  own  country,  and  by  Arago, 
Quetelet,  and  others,  in  Europe.  These  examina- 
tions led  to  the  discovery  of  ten  undoubted  returns 
of  the  November  shower  previous  to  that  of  1799. 
The  descriptions  of  these  former  meteoric  falls  are 


SHOOTING-STARS.  73 

given  by  Professor  II.  A.  Newton  in  the  American 
Journal  of  Science,  for  May,  1864.  They  occurred 
in  the  years  902,  931,  934,  1002,  1101,  1202,  1366, 
1533,  1602,  and  1698.  Historians  represent  the  me- 
teors of  A.D.  902  as  innumerable,  and  as  moving 
like  rain  in  all  directions.  The  exhibition  of  1202 
was  scarcely  less  magnificent.  "On  the  last  day  of 
Muharrem,"  says  a  writer  of  that  period,  "  stars 
shot  hither  and  thither  in  the  heavens,  eastward  and 
westward,  and  flew  against  one  another  like  a  scat- 
tering swarm  of  locusts,  to  the  right  and  left;  this 
phenomenon  lasted  until  daybreak;  people  were 
thrown  into  consternation,  and  cried  to  God  the 
Most  High  with  confused  clamor."  The  shower  of 
1366  is  thus  described  in  a  Portuguese  chronicle, 
quoted  byllumboldt:  "In  the  year  1366,  twenty- 
two  days  of  the  month  of  October  being  past,  three 
months  before  the  death  of  the  king,  Don  Pedro 
(of  Portugal),  there  was  in  the  heavens  a  movement 
of  stars  such  as  men  never  before  saw  or  heard  of. 
At  midnight,  and  for  some  time  after,  all  the  stars 
moved  from  the  east  to  the  west;  and  after  beino- 

o 

collected  together,  they  began  to  move,  some  in  one 
direction  and  others  in  another.  And  afterward 
they  fell  from  the  sky  in  such  numbers,  and  so 
thickly  together,  that  as  they  descended  low  in  the 
air  they  seemed  large  and  fiery,  and  the  sky  and 
the  air  seemed  to  be  in  flames,  and  even  the  earth 
appeared  as  if  ready  to  take  fire.  That  portion  of 
the  sky  where  there  were  no  stars  seemed  to  be 
divided  into  many  parts,  and  this  lasted  for  a  long 
time." 

t 


74  COMETS   AND   METEORS. 


The  Showers  of  1866-9. 

The  fact  that  all  great  displays  of  the  November 
meteors  have  taken  place  at  intervals  of  33  or  34 
years,  or  some  multiple  of  that  period,  had  led  to  a 
general  expectation  of  a  brilliant  shower  in  1866. 
In  this  country,  however,  the  public  curiosity  was 
much  disappointed.*  The  numbers  seen  were 
greater  than  on  ordinary  nights,  but  not  such  as 
would  have  attracted  any  special  attention.  The 
greatest  number  recorded  at  any  one  station  was 
seen  at  New  Haven  by  Professor  Newton.  On  the 
night  of  the  12th  694  were  counted  in  five  hours  and 
twenty  minutes,  and  on  the  following  night,  881  in 
five  hours.  A  more  brilliant  display  was,  however, 
witnessed  in  Europe.  Meteors  began  to  appear  in 
unusual  frequency  about  11  o'clock  on  the  night  of 
the  13th,  and  their  numbers  continued  to  increase 
with  great  rapidity  for  more  than  two  hours ;  the 
maximum  being  reached  a  little  after  1  o'clock.  A 
writer  in  Edinburgh,  Scotland,  thus  describes  the 
phenomenon  as  observed  at  that  city: — "Standing 
on  the  Calton  Hill,  and  looking  westward, — with 
the  observatory  shutting  out  the  lights  of  Princes 
Street, — it  was  easy  for  the  eye  to  delude  the  im- 
agination into  fancying  some  distant  enemy  bom- 
barding Edinburgh  Castle  from  long  range;  and 
the  occasional  cessation  of  the  shower  for  a  few 


*  The  first  indication  of  the  approaching  shower  was  the  ap- 
pearance of  meteors  in  unusual  numbers  at  Malta,  on  the  13th  of 
November,  1864.  In  1865,  as  observed  at  Greenwich  and  other 
stations,  they  were  still  more  numerous. 


SHOOTING-STARS.  75 

seconds,  only  to  break  out  again  with  more  numer- 
ous and  more  brilliant  drops  of  tire,  served  to  coun- 
tenance this  fancy.  Again,  turning  eastward,  it  was 
possible  now  and  then  to  catch  broken  glimpses  of 
the  train  of  one  of  the  meteors  through  the  grim 
dark  pillars  of  that  ruin  of  most  successful  manu- 
facture, the  National  Monument;  and  in  fact  from 
no  point  in  or  out  of  the  city  was  it  possible  to 
watch  the  strange  rain  of  stars,  pervading  as  it  did 
all  points  of  the  heavens,  without  pleased  interest 
and  a  kindling  of  the  imagination,  and  often  a 
touch  of  deeper  feeling  that  bordered  on  awe."  At 
London  about  1  o'clock  a  single  observer  counted 
200  in  two  minutes.  The  whole  number  seen  at 
Greenwich  was  8485.  The  shower  was  also  observed 
in  different  countries  on  the  continent. 

In  1867  the  display  was  generally  observed 
throughout  the  United  States.  From  the  able  and 
interesting  reports  of  Commodore  Sands  and  Pro- 
fessors Newcomb,  Harkness,  and  Eastman,  we  de- 
rive the  following  facts  in  regard  to  the  shower  as 
seen  at  Washington,  D.  C.: 

Commencement \h.    Om.  A.M.  Nov.  14. 

Maximum 4    20         "  " 

End 5      0        "  " 

Number  of  meteors  per  hour  at  maximum 3000 

Mean  height  on  first  appearance 75  miles. 

"          u      on  disappearance 55     " 

Position  of  radiant,  R.  A.  151°,  Decl.  22 £°. 

The  shower  of  1868  was  in  some  respects  quite 
remarkable,  though  the  number  of  meteors  was  less 
than  in  1866  or  1867.  At  New  Haven  the  fall  com- 
menced about  midnight,  and  from  2  o'clock  till  day- 


76  COMETS   AND   METEORS. 

break  over  5000  meteors  were  counted.  The  time 
of  maximum  could  not  be  accurately  determined, 
as  no  decrease  in  the  numbers  was  observable  till 
dawn.  The  display  was  also  witnessed  in  England 
and  in  Cape  Colony,  South  Africa.  The  times  of 
maxima  in  these  countries  differed  so  materially  as 
to  indicate  a  decided  stratification  of  the  meteoric 
stream.  The  entire  depth,  moreover,  where  crossed 
by  the  earth  in  1868,  was  much  greater  than  at  the 
part  traversed  either  iu  18d6  or  1867. 

In  1869  the  shower  was  observed  at  Port  Sa'id, 
Lower  Egypt,  by  G.  L.  Tupman,  Esq.;  in  Florida, 
U.  S.,  by  Commander  William  Gibson,  TJ.S.K  ; 
and  at  Santa  Barbara,  California,  by  Mr.  G.  David- 
son and  Mrs.  E.  Davidson.  The  first  observed  112 
meteors  in  Ih.  54m.,  from  2h.  30m.  to  4h.  24m., 
Alexandria  mean  time;  the  numbers  during  this 
interval  being  nearly  equal,  though  slightly  decreas- 
ing. Throughout  the  morning  (November  14)  the 
sky  was  only  partly  clear.  The  two  observers 
at  Santa  Barbara  saw  556  in  2h.  25rn.,  ending  at 
3h.  43m.  A.M.  In  Florida  also  the  display  was 
quite  brilliant,  though  inferior  to  that  of  1868.  It 
should  be  remarked  that  the  morning  in  many  parts 
of  the  United  States  was  cloudy.  No  considerable 
number  of  the  meteors  of  this  stream  has  been  ob- 
served in  any  part  of  the  world  since  1869. 

DISCUSSION   OF   THE   PHENOMENA. 

Since  the  memorable  display  of  November  13, 
1833,  the  phenomena  of  shooting-stars  have  been 
observed  and  discussed  with  a  very  lively  interest. 


SHOOTING-STARS.  77 

Among  the  first  laborers  in  this  department  of  re- 
search the  names  of  Olmsted,  Herrick,  and  Twin- 
ing must  ever  hold  a  conspicuous  place.  The  fact 
that  the  position  of  the  radiant  point  did  not  change 
with  the  earth's  rotation  at  once  placed  the  cosmi- 
cal  origin  of  the  meteors  wholly  beyond  question. 
The  theory  of  a  ring  of  nebulous  matter  revolving 
round  the  sun  in  an  elliptic  orbit — a  theory  some- 
what different  from  that  proposed  by  Olmsted — 
was  found  to  afford  a  simple  and  satisfactory 
explanation  of  the  phenomena.  This  hypothesis 
of  an  eccentric  stream  of  meteors  intersecting  the 
earth's  orbit  was  adopted  by  Humboldt,  Arago,  and 
others,  shortly  after  the  occurrence  of  the  meteoric 
shower  of  1833. 

A  few  years  previous  to  the  display  of  1866  it 
was  shown  by  Professor  Newton,  of  Yale  College, 
that  the  distribution  of  meteoric  matter  around  the 
ring  or  orbit  is  far  from  uniform  ;  that  the  motion 
is  retrograde ;  that  the  node  of  the  orbit  has  an  an- 
nual forward  motion  of  102".6  with  respect  to  the 
equinox,  or  of  52". 4  with  respect  to  the  fixed  stars ; 
that  the  periodic  time  must  be  limited  to  five 
accurately  determined  periods,  viz.:  180.05  days, 
185.54  days,  354.62  days,  376.5  days,  or  33.25  years; 
and  that  the  inclination  of  the  orbit  to  the  ecliptic 
is  about  17°.  Professor  Newton,  for  reasons  as- 
signed, regarded  the  third  period  named  as  the 
most  probable.  He  remarked,  however,  that  by 
computing  the  secular  motion  of  the  node  for  each 
periodic  time,  and  comparing  the  result  with  the 
known  precession,  it  was  possible  to  determine 
which  of  the  five  periods  is  the  correct  one. 

7* 


78  COMETS    AND   METEORS. 

For  the  application  of  this  crucial  test, — a  prob- 
lem of  more  than  ordinary  interest, — we  are  in- 
debted to  Professor  J.  0.  Adams,  of  Cambridge, 
England.  By  an  elegant  analysis  it  was  first  shown 
that  for  either  of  the  iirst  four  periods  designated 
by  Professor  Newton,  the  annual  motion  of  the 
node,  resulting  from  planetary  perturbation,  would 
be  considerably  less  than  one  half  of  the  observed 
motion.  It  only  remained,  therefore,  to  examine 
whether  the  period  of  33J  years  would  give  a  mo- 
tion of  the  node  corresponding  with  observation. 
Professor  Adams  found  that  in  this  time  the  longi- 
tude of  the  node  is  increased  20'  by  the  action  of 
Jupiter,  V  by  the  action  of  Saturn,  and  V  by  that 
of  Uranus.  The  effect  of  the  other  planets  is 
scarcely  perceptible.  The  calculated  motion  in  33  J 
years  is  therefore  28'.  The  observed  motion  in  the 
same  time,  according  to  Professor  Newton,  as  pre- 
viously stated,  is  29'.  This  remarkable  accordance 
was  at  once  accepted  by  astronomers  as  satisfactory 
evidence  that  the  period  is  about  33.25  years. 

Having  determined  the  periodic  time,  the  mean 
distance,  or  semi-axis  major,  is  found  by  Kepler's 
third  law  to  be  10.34.  The  aphelion  is  consequently 
situated  at  a  comparatively  short  distance  beyond  the 
orbit  of  Uranus.  The  orbit  is  represented  in  Fig.  4. 

It  was  stated  at  the  close  of  Chapter  VI.  that 
shooting-stars  are  the  dissevered  fragments  of 
cometic  matter,  which,  penetrating  our  atmosphere, 
are  rendered  luminous  by  the  resistance  so  encoun- 
tered. The  discovery  that  comets  and  meteors  are 
actually  moving  in  the  same  orbits  was  first  an- 
nounced by  Signor  Schiaparelli  in  1867.  The 


SHOOTING-STARS. 


79 


coincidence  of  the  orbits  of  Tempel's   comet*  as 
computed   by   Dr.   Oppolzer,   and   the   meteors   of 

Fig.  4. 


November  14  as  determined  by  Schiaparelli,  is 
too  close  to  be  regarded  as  merely  accidental. 
These  elements  are  as  follows  : 

Nov.  Meteors.  Tempel's  Comet. 

Perihelion  passage Nov.  10.092,  1866.  Jan.  11.160,  1866. 

Passage  of  descending  node.  Nov.  13.576, 

Longitude  of  perihelion 56°  26'  60°  28' 

Longitude  of  ascending  node...  231°  28'  231°  26' 

*  See  page  30. 


80  .COMETS   AND   METEORS. 

Nov.  Meteors.  Tempers  Comet. 

Inclination 17°  44'  17°  18' 

Perihelion  distance 0.9873  0.9765 

Eccentricity 0.9046  0.9054 

Semi-major  axis 10.3400  10.3240 

Periodic  time 33.2500  y.  33.1760  y. 

Motion Retrograde.  Retrograde. 

The  fact  is  thus  obvious  that  the  meteors  of  No- 
vember 14  are  the  products  of  the  comet's  gradual 
dissolution.  It  has  been  stated  that  the  comets  of 
1366  and  1866  are  probably  identical.  The  interval 
indicates  a  period  of  33.283  years — greater  by  39 
days  than  that  found  by  Oppolzer.  With  this 
value  of  the  periodic  time  and  the  known  secular 
variation  of  the  node  it  is  found  that  the  cornet 
and  Uranus  were  in  close  proximity  about  the  be- 
ginning of  the  year  547  B.C.  It  is  therefore  not  im- 
probable that  the  former  was  then  thrown  into  its 
present  orbit  by  the  attraction  of  the  latter.  The 
celebrated  Leverrier  designated  the  year  126  of  our 
era  as  the  probable  epoch  of  the  comet's  entrance 
into  our  system.  This  date,  however,  is  incompat- 
ible with  the  period  here  adopted.  It  is  worthy  of 
remark,  moreover,  as  bearing  on  this  question,  that 
the  extension  of  the  cluster  in  the  tenth  century,  as 
indicated  by  the  showers  of  902,  931,  and  934,  was 
too  great  to  have  been  effected  in  so  short  a  period 
as  800  years. 

With  the  period  of  33.283  years  it  is  easy  to  find 
that  the  comet  will  make  a  near  approach  to  the  earth 
about  the  16th  or  17th  of  November,  1965,  and  to 
Uranus  in  1983.  At  one  of  these  epochs  the  comet- 
ary  orbit  will  probably  undergo  considerable  trans- 
formation. 


SHOOTING-STARS.  81 

"We  have  seen  that  the  comet  of  1866,  and  also 
the  meteoroids  following  in  its  path,  have  their 
perihelion  at  the  orbit  of  the  earth,  and  their  aphe- 
lion at  the  orbit  of  Uranus.  Both  planets,  therefore, 
at  each  encounter  with  the  current  not  only  appro- 
priate a  portion  of  the  meteoric  matter,  but  entirely 
change  the  orbits  of  many  meteoroids.  In  regard 
to  the  devastation  produced  by  the  earth  in  passing 
through  the  cluster,  it  is  sufficient  to  state  that,  ac- 
cording to  Weiss,  the  meteor  orbits  resulting  from 
the  disturbance  will  have  all  possible  periods  from 
21  months  to  390  years.  It  may  be  regarded,  there- 
fore, as  evidence  of  the  recent*  introduction  of  this 
meteor-stream  into  the  solar  system  that  the  comet 
of  1866,  which  constitutes  a  part  of  the  cluster,  has 
not  been  deflected  from  the  meteoric  orbit  by  either 
the  earth  or  Uranus. 

*  Recent  in  comparison  with  the  origin  of  the  August  meteors, 
which  constitute  a  continuous  ring. 


CHAPTER    IX. 


OTHER    METEORIC    STREAMS. 

The  Meteors  of  August  7-11. — Muschenbroek,  in 
his  "Introduction  to  Natural  Philosophy,"  published 
in  1762,  stated  as  the  result  of  his  own  observations 
that  shooting-stars  are  more  abundant  in  August 
than  in  any  other  part  of  the  year.  The  fact,  how- 
ever, that  a  maximum  occurs  on  the  9th  or  10th  of 
the  month  was  first  shown  by  Quetelet  in  1835. 
Since  that  time  the  shower  has  been  regularly  ob- 
served both  in  Europe  and  America;  the  number 
of  meteors  at  the  maximum  sometimes  amounting 
to  160  per  hour.  Their  tracks  when  produced  back- 
ward intersect  each  other  at  a  particular  point  in 
the  constellation  Perseus. 

Of  the  315  meteoric  displays  given  in  Quetelet's 
catalogue,  63  belong  to  the  August  epoch.  Their 
dates  up  to  the  commencement  of  the  present  cen- 
tury are  as  follows : 


1. 

2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 


A.D.     811,  July  25th. 


820, 

25th-30th. 

824, 

26th-28th. 

830, 

26th. 

833, 

27th. 

835, 

26th. 

841, 

25th-30th 

924, 

27th-30th. 

925, 

27th-30th. 

926, 

27th-30th. 

82 


OTHER,   METEORIC   STREAMS.  83 

11. AD.    933,  July  25th-30th. 

12 1243,  Aug.  2d. 

13 1451,     «  7th. 

14 1709,     «  8th. 

15 1779,     «  9th-10th. 

16 1781,     "  8th. 

17 1784,     "  6th-9th. 

18 1789,     "  10th. 

19 1798,     «  9th. 

20 1799,     "  9th-10th. 

21 1800,     "  10th. 

As  the  earth  is  about  five  days  in  crossing  the 
ring,  its  breadth  in  some  parts  cannot  be  less  than 
8,000,000  miles. 

In  1866  Professor  Schiaparelli,  on  computing  the 
orbit  of  this  meteoric  stream,  noticed  the  remark- 
able agreement  of  its  elements  with  those  of  Swift's 
or  Tattle's  comet*  (1862,111.),  as  computed  by  Dr. 
Oppolzer.  These  coincidences  are  exhibited  in  the 
following  table: 

Meteors  of  August  10.       Comet  III.  of  1862. 

Longitude  of  perihelion 343°  387  344°  41' 

Ascending  node 138°  16'  137°  27' 

Inclination 63°    3'  66°  25' 

Perihelion  distance 0.9643  0.9626. 

Period 105  years  (?)  121.5  years. 

Motion Retrograde.  Retrograde. 

It  appears,  therefore,  that  the  third  comet  of  1862 
is  a  part  of  the  meteoric  stream  whose  orbit  is 
crossed  by  the  earth  on  the  10th  of  August. 

The  characteristics  of  different  meteor-zones  afford 
interesting  indications  in  regard  to  their  relative  age, 

*  Mr.  Swift,  of  Marathon,  N.  Y.,  had  two  or  three  days  pri- 
ority in  the  discovery  of  this  comet,  but  unfortunately  delayed 
his  announcement  of  the  fact. 


84  COMETS    AND    METEORS. 

the  magnitude  and  composition  of  their  corpus- 
cles, etc.  Thus,  if  we  compare  the  streams  of 
August  10  and  November  14,  we  shall  find  that 
the  former  probably  entered  our  system  at  a  com- 
paratively remote  epoch.  We  have  seen  that  at  each 
return  to  perihelion  the  meteoric  cluster  is  extended 
over  a  greater  arc  of  its  orbit.  Now,  Tattle's  comet 
and  the  August  meteors  undoubtedly  constituted  a 
single  group  previous  to  their  entering  the  solar 
domain.  It  is  evident,  however,  from  the  annual 
return  of  the  shower  during  the  last  90  years,  that 
the  ring  is  at  present  nearly  if  not  quite  continuous. 
That  the  meteoric  mass  had  completed  many  revo- 
lutions before  the  ninth  century  of  our  era  is  mani- 
fest from  the  frequent  showers  observed  between 
the  years  811  and  841.  At  the  same  time,  the  long 
interval  of  83  years  between  the  last  observed  dis- 
play in  the  ninth  century,  and  the  first  in  the  tenth, 
seems  to  indicate  the  existence  of  a  wide  chasm  in 
the  ring  no  more  than  a  thousand  years  since. 

Neither  the  period  of  the  meteors  nor  that  of  the 
comet  can  yet  be  regarded  as  accurately  ascertained. 
The  latter,  however,  in  all  probability,  exceeds  the 
former  by  several  years.  Now,  at  each  passage  of 
the  earth  through  the  elliptic  stream,  those  meteor- 
oids  nearest  the  disturbing  body  must  be  thrown 
into  orbits  differing  more  or  less  from  that  of  the 
primitive  group.  In  like  manner  the  near  approach 
of  the  comet  to  the  earth  at  an  ancient  epoch  may 
account  for  the  lengthening  of  its  periodic  time. 


OTHER    METEORIC    STREAMS.  85 


The  Meteors  of  November  27. 

Professor  Scbiaparelli's  brilliant  discovery  of  the 
relation  between  comets  and  meteors  may  now  be 
ranked  with  the  established  truths  of  astronomy. 
His  hypothesis,  however,  in  regard  to  the  origin  of 
meteoric  streams  has  not  been  generally  accepted. 
Comets  and  meteors,  according  to. his  theory,  are 
derived  from  cosmical  clouds  existing  in  great  num- 
bers in  stellar  space.  These  nebulae,  in  consequence 
of  their  own  motion  or  that  of  the  sun,  are  drawn 
towards  the  centre  of  our  system.  By  the  unequal 
influence  of  the  sun's  attraction  on  different  parts, 
such  clouds  are  transformed  into  currents  of  great 
length  before  reaching  the  limits  of  the  planetary 
system.  Shooting -stars,  fire-balls,  aerolites,  and 
comets  being  all  of  the  same  nature,  differing  merely 
in  size,  sometimes  fall  towards  the  sun  as  parts  of 
the  same  current. 

The  views  of  Dr.  Weiss,  of  Vienna,  differ  from 
those  of  Schiaparelli,  in  that  he  regards  comets  as 
the  original  bodies  by  whose  disintegration  meteor- 
streams  are  gradually  formed.*  "  Cosmical  clouds," 
he  remarks,  "  undoubtedly  appear  in  the  universe, 
but  only  of  such  density  that  in  most  cases  they 
possess  sufficient  coherence  to  withstand  the  destruc- 
tive operation  of  the  sun's  attraction,  not  only  up 
to  the  boundaries  of  our  solar  system,  but  even 
within  it.  Such  cosmical  clouds  will  always  appear 
to  us  as  comets  when  they  pass  near  enough  to  the 

*  Astr.  Nach.,  Nos.  1710,  1711.  For  a  fuller  statement  of 
Schiaparelli's  theory,  see  Silliman's  Journal  for  May,  1867. 

8 


86  COMETS   AND    METEORS. 

earth  to  become  visible.  Approaching  the  sun, 
the  comet  undergoes  great  physical  changes,  which 
finally  affect  the  stability  of  its  structure :  it  can  no 
longer  hold  together:  parts  of  it  take  independent 
orbits  around  the  sun,  having  great  resemblance  to 
the  orbit  of  the  parent  comet.  "With  periodical 
comets,  this  process  is  repeated  at  each  successive 
approach  to  the  sun.  Gradually  the  products  of 
disintegration  are  distributed  along  the  comet's 
orbit,  and  if  the  earth's  orbit  cuts  this,  the  phe- 
nomenon of  shooting-stars  is  produced." 

These  views  of  the  distinguished  astronomer  of 
Vienna  are  confirmed  by  the  star-shower  of  Novem- 
ber  27,  1872.  That  the  orbits  of  the  earth  and 
Biela's  comet  intersect  at  the  point  passed  by  the 
former  about  the  last  of  November,  and  that  in 
1845  the  comet  separated  into  two  visible  parts,  has 
been  stated  in  a  'previous  chapter.  The  comet's 
non-appearance  in  December,  1865,  and  in  Septem- 
ber, 1872,  was  regarded  by  astronomers  as  presump- 
tive evidence  of  its  progressive  dissolution.  A  me- 
teoric shower,  resulting  from  the  earth's  collision 
with  the  cometary  debris,  was  accordingly  expected 
about  the  27th  of  November. 

The  first  indication  of  the  approaching  display 
appeared  on  the  evening  of  November  24,  when 
meteors  in  unusual  numbers  were  observed  by  Pro- 
fessor Newton,  at  New  Haven,  Connecticut.  On 
Wednesday  evening,  the  27th,  from  the  close  of 
twilight  till  8  o'clock,  a  decided  shower  of  shooting- 
stars  was  noticed  in  various  parts  of  the  United 
States.  At  Greencastle,  Indiana,  Professor  Joseph 
Tingiey  counted  110  meteors  in  40  minutes,  and  at 


OTHER    METEORIC    STREAMS.  87 

Princeton,  in  the  same  State,  Mr.  D.  Eckley  Hunter 
counted  70  in  80  minutes.  The  numbers  seen  at 
New  Haven  were  considerably  greater.  The  fact 
that  the  display  commenced  before  daylight  had 
entirely  closed  seemed  to  indicate  that  only  the 
termination  of  the  shower  had  been  observed  in 
this  country.  Accordingly  the  display  was  soon 
found  to  have  been  witnessed  from  60°  E.  to  90°  W. 
of  Greenwich,  or  through  150°  of  longitude.  In 
England  the  first  bolide  of  the  swarm  was  seen  by 
M.  M.  Brinkley,  at  3  o'clock,  P.M.,  in  full  daylight. 
The  meteors  were  most  numerous  in  the  southern 
part  of  the  continent,  particularly  in  Italy.  At  the 
Observatory  of  Breslau,  according  to  M.  Faye,  3000 
were  seen  from  6h.  30m.  to  7h.  50m.  Dr.  Heis  re- 
ported that  at  Miinster  2500  per  hour  were  counted 
by  two  observers.  At  Naples,  Signor  Gasparis  ob- 
served two  meteors  per  second.  At  Turin,  M.  Denza, 
Director  of  the  Observatory,  reported  33,400  in  6h. 
30m.;  many  of  various  and  delicate  colors,  and 
followed  by  long  and  brilliant  trains.  At  some 
points  the  numbers  were  so  great  that  an  accurate 
enumeration  was  wholly  impossible.  In  short,  the 
display  was  decidedly  the  most  brilliant  that  has 
occurred  since  that  of  November  13,  1833. 
.  But  some  of  the  most  interesting  circumstances 
in  connection  with  the  phenomena  of  November 
27,  1872,  remain  to  be  detailed.  Astronomers  with- 
out exception  regarded  the  display  as  due  to  the 
earth's  passage  through  the  debris  following  in  the 
path  of  Biela's  comet.  In  accordance  with  this  view 
Dr.  Klinkerfues,  of  Gottingen,  concluded  that  the 
comet  itself,  or  rather  its  largest  portion,  ought  to 


88  COMETS   AND    METEORS. 

be  found  in  the  region  of  the  heavens  nearly  opposite 
to  that  from  which  the  meteoroids  appeared  to  radi- 
ate.* As  this  point  in  the  southern  hemisphere 
could  not  he  observed  in  Europe,  he  conceived  the 
happy  idea  of  detecting  the  fugitive  by  means  of  the 
electric  telegraph.  The  following  was  accordingly  dis- 
patched to  Mr.  Pogson,  Director  of  the  Government 
Observatory  at  Madras,  in  Southern  India:  "Biela 
touched  earth  on  27th;  search  near  Theta  Centauri."  The 
first  two  mornings  after  the  receipt  of  this  dispatch 
were  cloudy  at  Madras.  On  the  third,  however,  the 
cometary  fragment  was  found,  and  its  motion  ac- 
curately measured.  The  observer  described  it  as 
circular  and  rather  bright,  with  no  traces  of  a  tail. 
But  one  fragment  could  be  detected.  On  the  next 
morning,  December  3,  the  comet  was  again  observed. 
Its  diameter  had  sensibly  increased ;  it  had  a  bright 
nucleus,  and  still  presented  a  circular  aspect.  A  faint 
tail  was  also  noticed,  equal  in  length  to  one-fourth 
of  the  moon's  apparent  diameter.  The  following 
mornings  being  again  cloudy,  no  further  observa- 
tions could  be  obtained.  This  cometary  mass  will 
be  in  close  proximity  to  the  earth  about  the  last  of 
November,  1892.  Another  brilliant  meteoric  shower 
may  therefore  be  expected  at  that  epoch. 


The  Meteors  of  April  20. 

Meteoric  showers  have  occurred  about  the  20th 
of  April  in  the  following  years  : 

*  The  radiant  of  the  Eiela  meteors  is  near  Gamma  Andromedse. 


OTHER    METEORIC    STREAMS.  89 

B.C.     687 

15 

A.D.     582 

1093 

1094 

1095 

1096 

1122) 

1123] 

1803 

The  probability  that  these  meteors  are  derived 
from  a  ring  which  intersects  the  earth's  orbit,  was 
first  suggested  by  Arago  in  1836.  A  comparison  of 
dates  led  Herrick  to  designate  27  years  as  the  proba- 
ble period  of  the  cluster.  In  the  Astronomische  Nach- 
richten,  No.  1632,  Dr.  Weiss  called  attention  to  the 
fact  that  the  orbit  of  the  first  comet  of  1861  very 
nearly  intersects  that  of  the  earth,  in  longitude 
210° — the  point  passed  by  the  latter  at  the  epoch 
of  the  April  meteoric  shower.  A  relation  between 
the  meteors  and  the  comet,  indicating  an  approx- 
imate equality  of  periods,  was  thus  suggested  as 
probable.  But  the  come£,  according  to  Oppolzer, 
does  not  complete  a  revolution  in  less  than  415 
years.  If,  therefore,  the  meteoric  period  is  nearly 
the  same,  the  known  dates  of  star-showers  indicate 
a  diffusion  of  meteoroids  around  one  half  of  the 
orbit  previous  to  the  display  of  the  year  15  B.C.  No 
subsequent  perturbation,  then,  of  a  particular  part 
could  sensibly  afiect  the  general  orbit  of  the  stream. 
The  infrequency  of  the  display  renders,  therefore, 
the  hypothesis  of  a  long  period  extremely  improb- 
able. 

The  entire  interval  between  687  B.C.  and  A.D.  1803 
8* 


90  COMETS   AND    METEORS. 

is  2490  years,  or  92  periods  of  27.0652  years;  and 
the  known  dates  are  all  satisfied  by  the  following 
scheme : 

B.C.    687  to  B.C.      15....  672  years  =  25  periods  of  26.8800 y.  each. 
15  to  A.D.    582... .597      "    =22  »          27.1363         " 

A.D.  582  to  1095... .513  "  =19  "  27.0000  " 
1095  to  1122....  27  "  =  1  "  27.0000  " 
1122  to  1803... .681  "  =25  "  27.2400  « 

With  a  period  of  27  years,  the  perihelion  being 
interior  to  the  earth's  orbit,  the  aphelion  distance  of 
the  meteors  would  be  very  nearly  equal  to  the  dis- 
tance of  Uranus.  The  next  shower,  if  the  assumed 
period  be  correct,  ought  to  occur  about  1884.  It  is 
worthy  of  remark  that  near  the  time  of  the  last 
(hypothetical)  return  Mr.  Du  Chaillu  witnessed  the 
meteors  of  this  epoch,  in  considerable  numbers,  in 
the  interior  of  Africa. 


The  Meteors  of  December  12. 

Meteoric  showers  have  occurred  about  the  12th 
of  December  in  the  following  years: 

1.  A.D.  901.    "The  whole  hemisphere  was  filled 
with  those   meteors  called  falling-stars  from  mid- 
night till  morning,  to  the  great  surprise  of  the  be- 
holders in  Egypt." 

2.  In   930  a  remarkable  shower  of  falling  stars 
was  observed  in  China. 

3.  Extraordinary  meteoric  phenomena  were  ob- 
served at  Zurich  at  the  same  epoch  in  1571. 

4.  On  the  night  of  the  llth  and  12th  of  Decem- 
ber, 1833,  a  great  number  of  shooting-stars  were 


OTHER    METEORIC    STREAMS.  91 

seen  at  Parma.  At  the  maximum  as  many  as  ten 
were  visible  at  the  same  time. 

5.  (Doubtful.)  1861,  1862,  and  1863.  Maximum 
probably  in  1862.  The  meteors  at  this  return  were 
far  from  being  comparable  in  numbers  with  the  an- 
cient displays.  The  shower,  however,  was  distinctly 
observed.  E.  P.  Greg,  Esq.,  of  Manchester,  Eng- 
land, says  the  period  of  December  12,  1862,  was 
"  exceedingly  well  defined." 

These  dates  indicate  a  period  of  about  29J  years. 
Thus: 

901  to    930 1  period  of  29.000  years. 

930  to  1571 22  periods  of  29.136  " 

1571  to  1833 9  periods  of  29.111  " 

1833  to  1862 1  period  of  29.000  " 


Meteors  of  October  16-20. 

Meteoric  showers  were  observed  from  the  16th  to 
the  20th  of  October  in  the  years  288,  1436,  1439, 
1743,  and  1798.  These  dates  render  it  somewhat 
probable  that  the  period  is  about  27  J  years.  Thus : 

A.D.    288  to  1439 42  periods  of  27.405  years  each. 

1439  to  1743.. 11  "         27.636      "        " 

1743  to  1798 2          "         27.500      "        " 

If  these  periods  are  correct,  it  is  a  remarkable 
coincidence  that  the  aphelion  distances  of  the  me- 
teoric rings  of  April  20,  October  18,  November  14, 
and  December  12,  as  well  as  those  of  the  comets 
1866  L,  and  1867  I.,  are  all  nearly  equal  to  the 
mean  distance  of  Uranus. 


92  COMETS   AND    METEORS. 

The  Meteors  of  April  30,  May  1. 

Professor  Schiaparelli,  in  his  list  of  meteoric 
showers  whose  radiant  points  are  derived  from  ob- 
servations made  in  Italy  during  the  years  1868, 1869, 
and  1870,  describes  one  as  occurring  on  April  30 
and  May  1;  the  radiant  being  in  the  Northern 
Crown.  The  same  shower  has  also  been  recognized 
by  R.  P.  Greg,  F.R.S.,  of  Manchester,  England. 
This  meteor-stream,  it  is  now  proposed  to  show,  is 
probably  derived  from  one  much  more  conspicuous 
in  ancient  times. 

In  Quetelet's  "  Physique  du  Globe"  we  find  mete- 
oric displays  of  the  following  dates.  In  each  case  the 
corresponding  day  for  1870  is  also  given,*  in  order 
to  exhibit  the  close  agreement  of  the  epochs : 

1.  A.D.    401,  April    9th;  corresponding  to  April  29th,  for  1870. 


2. 

538, 

"        6th; 

April  25th, 

3. 

839, 

"     17th; 

May  1st, 

4. 

927, 

"     17th; 

April  30th, 

5. 

934, 

"     18th; 

May  1st, 

6. 

1009, 

"     16th; 

April  28th, 

The  epochs  of  927  and  934  suggest  as  probable 
the  short  period  of  7  years.  It  is  found  accordingly 
that  the  entire  interval  of  608  years — from  401  to 
1009 — is  equal  to  89  mean  periods  of  6.8315  years 
each.  With  this  approximate  value  the  six  dates 
are  all  represented  as  follows  : 

From  A.D.  401  to  A.D.    538,  20  periods  of  6.85  years. 
538  to  839,  44          "          6.84      " 

839  to  927,  13          "          6.77      " 

927  to  934,    1          "          7.00     •" 

934  to          1009,  11          "          6.82      " 

*  Making  proper  allowance  for  the  precession  of  the  equinoxes. 


OTHER    METEORIC    STREAMS.  93 

This  period  nearly  corresponds  to  those  of  sev- 
eral comets  whose  aphelion  distances  are  somewhat 
greater  than  the  mean  distance  of  Jupiter.  So  long 
as  the  cluster  occupied  but  a  small  arc  of  the  orbit 
the  displays  would  evidently  be  separated  by  con- 
siderable intervals.  The  comparative  paucity  of 
meteors  in  modern  times  may  be  explained  by  the 
fact  that  the  ring  has  been  subject  to  frequent  per- 
turbations by  Jupiter. 


Groups  in  which  the  Meteoroids  are  sparsely  scattered. 

By  the  labors  of  Heis,Greg,Herschel,  Schiaparelli, 
and  others,  the  radiants  of  more  than  fifty  sparsely 
strewn  meteor-systems  have  been  determined.  Of 
these  the  following,  which  are  well  defined,  seem 
worthy  of  special  study: 

DATE.  POSITION  OF  RADIANT. 

R.  A.  N.  Decl. 

January  1-4 234°  51° 

January  18 232°  36° 

April  25 142°  53° 

The  orbits  and  periods,  except  in  the  few  cases 
previously  considered,  are  entirely  unknown.  Some 
of  the  observed  clusters  are  probably  the  debris  of 
ancient  comets  whose  aphelia  were  in  the  vicinity  of 
Jupiter's  orbit. 


CHAPTER    X. 

THE    ORIGIN   OF   COMETS   AND    METEORS. 

THE  fact  that  comets  and  meteors,  or  at  least  a 
large  proportion  of  such  bodies,  have  entered  the 
solar  system  from  stellar  space,  is  now  admitted  by 
all  astronomers.  The  question,  however,  in  regard 
to  the  origin  and  nature  of  these  cosmical  clouds 
still  remains  undecided.  The  theory  that  they  con- 
sist of  matter  expelled  with  great  velocity  from  the 
fixed  stars  appears  to  harmonize  the  greatest  num- 
ber of  facts,  and  is  accordingly  entitled  to  respect- 
ful consideration.  The  evidence  by  which  it  is  sus- 
tained may  be  briefly  stated  as  follows  : 

1.  The  observations  of  Zollner,  Respighi,  and 
others,  have  indicated  the  operation  of  stupendous 
eruptive  forces  beneath  the  solar  surface.  The  rose- 
colored  prominences,  which  Janssen  and  Lockyer 
have  shown  to  be  masses  of  incandescent  hydrogen, 
are  regarded  by  Professor  Respighi  as  phenomena 
of  eruption.  *'  They  are  the  seat  of  movements  of 
which  no  terrestrial  phenomenon  can  afford  any 
idea;  masses  of  matter,  the  volume  of  which  is 
many  hundred  times  greater  than  that  of  the  earth, 
completely  changing  their  position  and  form  in  the 
space  of  a  few  minutes."  The  nature  of  this 
eruptive  force  is  not  understood.  We  may  as- 
sume, however,  that  it  was  in  active  operation 
94 


THE   OEIGIN   OF   COMETS   AND   METEORS.  95 

long  before  the  sun  had  contracted  to  its  present 
dimensions. 

2.  With  an  initial  velocity  of  projection  equal  to 
380  miles  per  second,  the  matter  thrown  off  from 
the  sun  would  be  carried  beyond  the  limits  of  the 
solar  system,  never  to  return.    With  velocities  some- 
what less,  it  would  be  transported  to  distances  cor- 
responding to  those  of  the  aphelia  of  the  periodic 
comets. 

3.  On   the   7th  of   September,   1871,   Professor 
Young,  of  Dartmouth  College,*  witnessed  an  extra- 
ordinary explosion  on  the  sun's  surface.     The  ob- 
server, with  his   telescope,  followed   the   expelled 
matter  to  an  elevation  of  over  200,000  miles.     The 
mean  velocity  between  the  altitudes  of  100,000  and 
200,000  miles  was  166  miles  per  second.     This  rate 
of  motion  in  vacuo  would  indicate  an  initial  velocity 
of  about  260  miles  per  second.    But  the  sun  is  sur- 
rounded by  an  extensive  atmosphere,  whose  resist- 
ance must  have  greatly  retarded  the  velocity  of  the 
outrush  before  reaching  the  height  of  100,000  miles. 
The  original  velocity  of  these  hydrogen  clouds  was 
therefore  sufficient,  in  all  probability,  to  have  car- 
ried them,  if  unresisted,  beyond  the  solar  domain. 
Solid  or  dense  matter  propelled  with   equal  force 
would  doubtless  have  been  driven  off  never  to  re- 
turn, t 

^4.  This  eruptive  force,  whatever  be  its  nature,  is 
probably  common  to  the  sun  and  the  so-called  fixed 


*  Boston  Journal  of  Chemistry,  November,  1871. 
f  See  Mr.  Proctor's  interesting  discussion  of  this  subject  in  the 
Monthly  Notices  of  the  K.A.S.,  vol.  xxxii. 


96  COMETS    AND    METEORS. 

stars.  If  so,  the  dispersed  fragments  of  ejected 
matter  ought  to  be  found  in  the  spaces  intervening 
between  sidereal  systems.  Accordingly,  the  phe- 
nomena of  comets  and  meteors  have  demonstrated 
the  existence  of  such  matter,  widely  diffused,  in  the 
portions  of  space  through  which  the  solar  system  is 
moving. 

5.  According  to  Mr.  Sorby  the  microscopic  struc- 
ture of  the  aerolites  he  has  examined  points  evi- 
dently to  the  fact  that  they  have  been  at  one  time 
in  a  state  of  fusion  from  intense  heat, — a  fact  in 
striking  harmony  with  this  theory  of  their  origin. 

6.  The  velocity  with  which  some  meteoric  bodies 
have  entered  the  atmosphere  has  been  greater  than 
that  which  would   have  been  acquired  by  simply 
failing  toward  the  sun  from  any  distance,  however 
great.     On  the  theory  of  their  sidereal  origin,  this 
excess  of  velocity  has  been  dependent  on  the  primi- 
tive force  of  expulsion.     The  shower  of  aerolites 
which  fell  at  Pultusk,  Poland,  on  the  30th  of  Janu- 
ary, 1868,*  is  not  only  a  remarkable  illustration  of 
the  fact  here  stated,  but  also  of  another  which  may 
be  accounted  for  by  the  same   theory,   viz. :  that 
meteoric  bodies  sometimes  enter  the  solar  system  in 
groups  or  clusters. 

7.  A  striking  argument  in  favor  of  this  theory 
may  be  derived  from  the  researches  of  the  late  Pro- 
fessor Graham,  considered  in  connection  with  those 
of  Dr.  Huggins  and  other  eminent  spectroscopists. 
Professor  Graham  found  large  quantities  of  hydrogen 
confined  in  the  pores  or  cavities  of  certain  meteoric 

*  See  Chapter  VII. 


THE    ORIGIN    OF    COMETS    AND    METEORS. 


97 


masses.  Now,  the  spectroscope  has  shown  that  the 
sun's  rose-colored  prominences  consist  of  immense 
volumes  of  incandescent  hydrogen ;  that  the  same 
element  exists  in  great  abundance  in  many  of  the 
fixed  stars,  and  even  in  certain  nebulse ;  and  that 
the  star  in  the  Northern  Crown,  whose  sudden  out- 
burst in  1866  so  astonished  the  scientific  world,  af- 
forded decided  indications  of  its  presence. 


THE    END. 


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